diff --git a/src/libslic3r/Color.cpp b/src/libslic3r/Color.cpp
index d0437b681..7b5a7f3ba 100644
--- a/src/libslic3r/Color.cpp
+++ b/src/libslic3r/Color.cpp
@@ -3,7 +3,6 @@
 
 #include <random>
 
-#if ENABLE_COLOR_CLASSES
 static const float INV_255 = 1.0f / 255.0f;
 
 namespace Slic3r {
@@ -399,4 +398,3 @@ unsigned char picking_checksum_alpha_channel(unsigned char red, unsigned char gr
 
 } // namespace Slic3r
 
-#endif // ENABLE_COLOR_CLASSES
diff --git a/src/libslic3r/Color.hpp b/src/libslic3r/Color.hpp
index 6f39a26fc..fce0c67e0 100644
--- a/src/libslic3r/Color.hpp
+++ b/src/libslic3r/Color.hpp
@@ -1,8 +1,6 @@
 #ifndef slic3r_Color_hpp_
 #define slic3r_Color_hpp_
 
-#if ENABLE_COLOR_CLASSES
-
 #include <array>
 #include <algorithm>
 
@@ -169,6 +167,4 @@ extern unsigned char picking_checksum_alpha_channel(unsigned char red, unsigned
 
 } // namespace Slic3r
 
-#endif // ENABLE_COLOR_CLASSES
-
 #endif /* slic3r_Color_hpp_ */
diff --git a/src/libslic3r/Technologies.hpp b/src/libslic3r/Technologies.hpp
index ce374aba7..f2dddca07 100644
--- a/src/libslic3r/Technologies.hpp
+++ b/src/libslic3r/Technologies.hpp
@@ -45,13 +45,4 @@
 #define ENABLE_SPIRAL_VASE_LAYERS (1 && ENABLE_2_4_1_RC)
 
 
-//====================
-// 2.5.0.alpha1 techs
-//====================
-#define ENABLE_2_5_0_ALPHA1 1
-
-// Enable Color classes definition as unified point for colors manipulation
-#define ENABLE_COLOR_CLASSES (1 && ENABLE_2_5_0_ALPHA1)
-
-
 #endif // _prusaslicer_technologies_h_
diff --git a/src/slic3r/GUI/3DBed.cpp b/src/slic3r/GUI/3DBed.cpp
index ef99aeec0..21e23d402 100644
--- a/src/slic3r/GUI/3DBed.cpp
+++ b/src/slic3r/GUI/3DBed.cpp
@@ -19,15 +19,10 @@
 #include <boost/log/trivial.hpp>
 
 static const float GROUND_Z = -0.02f;
-#if ENABLE_COLOR_CLASSES
 static const Slic3r::ColorRGBA DEFAULT_MODEL_COLOR             = Slic3r::ColorRGBA::DARK_GRAY();
 static const Slic3r::ColorRGBA PICKING_MODEL_COLOR             = Slic3r::ColorRGBA::BLACK();
 static const Slic3r::ColorRGBA DEFAULT_SOLID_GRID_COLOR        = { 0.9f, 0.9f, 0.9f, 1.0f };
 static const Slic3r::ColorRGBA DEFAULT_TRANSPARENT_GRID_COLOR  = { 0.9f, 0.9f, 0.9f, 0.6f };
-#else
-static const std::array<float, 4> DEFAULT_MODEL_COLOR = { 0.235f, 0.235f, 0.235f, 1.0f };
-static const std::array<float, 4> PICKING_MODEL_COLOR = { 0.0f, 0.0f, 0.0f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
 
 namespace Slic3r {
 namespace GUI {
@@ -128,27 +123,15 @@ void Bed3D::Axes::render() const
     shader->set_uniform("emission_factor", 0.0f);
 
     // x axis
-#if ENABLE_COLOR_CLASSES
     const_cast<GLModel*>(&m_arrow)->set_color(-1, ColorRGBA::X());
-#else
-    const_cast<GLModel*>(&m_arrow)->set_color(-1, { 0.75f, 0.0f, 0.0f, 1.0f });
-#endif // ENABLE_COLOR_CLASSES
     render_axis(Geometry::assemble_transform(m_origin, { 0.0, 0.5 * M_PI, 0.0 }).cast<float>());
 
     // y axis
-#if ENABLE_COLOR_CLASSES
     const_cast<GLModel*>(&m_arrow)->set_color(-1, ColorRGBA::Y());
-#else
-    const_cast<GLModel*>(&m_arrow)->set_color(-1, { 0.0f, 0.75f, 0.0f, 1.0f });
-#endif // ENABLE_COLOR_CLASSES
     render_axis(Geometry::assemble_transform(m_origin, { -0.5 * M_PI, 0.0, 0.0 }).cast<float>());
 
     // z axis
-#if ENABLE_COLOR_CLASSES
     const_cast<GLModel*>(&m_arrow)->set_color(-1, ColorRGBA::Z());
-#else
-    const_cast<GLModel*>(&m_arrow)->set_color(-1, { 0.0f, 0.0f, 0.75f, 1.0f });
-#endif // ENABLE_COLOR_CLASSES
     render_axis(Geometry::assemble_transform(m_origin).cast<float>());
 
     shader->stop_using();
@@ -559,11 +542,7 @@ void Bed3D::render_default(bool bottom, bool picking) const
         if (!has_model && !bottom) {
             // draw background
             glsafe(::glDepthMask(GL_FALSE));
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(picking ? PICKING_MODEL_COLOR.data() : DEFAULT_MODEL_COLOR.data()));
-#else
-            glsafe(::glColor4fv(picking ? PICKING_MODEL_COLOR.data() : DEFAULT_MODEL_COLOR.data()));
-#endif // ENABLE_COLOR_CLASSES
             glsafe(::glNormal3d(0.0f, 0.0f, 1.0f));
             glsafe(::glVertexPointer(3, GL_FLOAT, m_triangles.get_vertex_data_size(), (GLvoid*)m_triangles.get_vertices_data()));
             glsafe(::glDrawArrays(GL_TRIANGLES, 0, (GLsizei)triangles_vcount));
@@ -573,14 +552,7 @@ void Bed3D::render_default(bool bottom, bool picking) const
         if (!picking) {
             // draw grid
             glsafe(::glLineWidth(1.5f * m_scale_factor));
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(has_model && !bottom ? DEFAULT_SOLID_GRID_COLOR.data() : DEFAULT_TRANSPARENT_GRID_COLOR.data()));
-#else
-            if (has_model && !bottom)
-                glsafe(::glColor4f(0.9f, 0.9f, 0.9f, 1.0f));
-            else
-                glsafe(::glColor4f(0.9f, 0.9f, 0.9f, 0.6f));
-#endif // ENABLE_COLOR_CLASSES
             glsafe(::glVertexPointer(3, GL_FLOAT, m_triangles.get_vertex_data_size(), (GLvoid*)m_gridlines.get_vertices_data()));
             glsafe(::glDrawArrays(GL_LINES, 0, (GLsizei)m_gridlines.get_vertices_count()));
         }
diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index b31315822..93f0548bc 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -344,7 +344,6 @@ void GLVolume::SinkingContours::update()
         m_model.reset();
 }
 
-#if ENABLE_COLOR_CLASSES
 const ColorRGBA GLVolume::SELECTED_COLOR         = ColorRGBA::GREEN();
 const ColorRGBA GLVolume::HOVER_SELECT_COLOR     = { 0.4f, 0.9f, 0.1f, 1.0f };
 const ColorRGBA GLVolume::HOVER_DESELECT_COLOR   = { 1.0f, 0.75f, 0.75f, 1.0f };
@@ -360,23 +359,6 @@ const std::array<ColorRGBA, 4> GLVolume::MODEL_COLOR = { {
     { 0.5f, 1.0f, 0.5f, 1.0f },
     { 0.5f, 0.5f, 1.0f, 1.0f }
 } };
-#else
-const std::array<float, 4> GLVolume::SELECTED_COLOR = { 0.0f, 1.0f, 0.0f, 1.0f };
-const std::array<float, 4> GLVolume::HOVER_SELECT_COLOR = { 0.4f, 0.9f, 0.1f, 1.0f };
-const std::array<float, 4> GLVolume::HOVER_DESELECT_COLOR = { 1.0f, 0.75f, 0.75f, 1.0f };
-const std::array<float, 4> GLVolume::OUTSIDE_COLOR = { 0.0f, 0.38f, 0.8f, 1.0f };
-const std::array<float, 4> GLVolume::SELECTED_OUTSIDE_COLOR = { 0.19f, 0.58f, 1.0f, 1.0f };
-const std::array<float, 4> GLVolume::DISABLED_COLOR = { 0.25f, 0.25f, 0.25f, 1.0f };
-const std::array<float, 4> GLVolume::SLA_SUPPORT_COLOR = { 0.75f, 0.75f, 0.75f, 1.0f };
-const std::array<float, 4> GLVolume::SLA_PAD_COLOR = { 0.0f, 0.2f, 0.0f, 1.0f };
-const std::array<float, 4> GLVolume::NEUTRAL_COLOR = { 0.9f, 0.9f, 0.9f, 1.0f };
-const std::array<std::array<float, 4>, 4> GLVolume::MODEL_COLOR = { {
-    { 1.0f, 1.0f, 0.0f, 1.f },
-    { 1.0f, 0.5f, 0.5f, 1.f },
-    { 0.5f, 1.0f, 0.5f, 1.f },
-    { 0.5f, 0.5f, 1.0f, 1.f }
-} };
-#endif // ENABLE_COLOR_CLASSES
 
 GLVolume::GLVolume(float r, float g, float b, float a)
     : m_sla_shift_z(0.0)
@@ -406,23 +388,6 @@ GLVolume::GLVolume(float r, float g, float b, float a)
     set_render_color(color);
 }
 
-#if !ENABLE_COLOR_CLASSES
-void GLVolume::set_color(const std::array<float, 4>& rgba)
-{
-    color = rgba;
-}
-
-void GLVolume::set_render_color(float r, float g, float b, float a)
-{
-    render_color = { r, g, b, a };
-}
-
-void GLVolume::set_render_color(const std::array<float, 4>& rgba)
-{
-    render_color = rgba;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 void GLVolume::set_render_color()
 {
     bool outside = is_outside || is_below_printbed();
@@ -452,25 +417,13 @@ void GLVolume::set_render_color()
             set_render_color(color);
     }
 
-    if (!printable) {
-#if ENABLE_COLOR_CLASSES
+    if (!printable)
         render_color = saturate(render_color, 0.25f);
-#else
-        render_color[0] /= 4;
-        render_color[1] /= 4;
-        render_color[2] /= 4;
-#endif // ENABLE_COLOR_CLASSES
-    }
 
     if (force_transparent)
-#if ENABLE_COLOR_CLASSES
         render_color.a(color.a());
-#else
-        render_color[3] = color[3];
-#endif // ENABLE_COLOR_CLASSES
 }
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA color_from_model_volume(const ModelVolume& model_volume)
 {
     ColorRGBA color;
@@ -488,34 +441,6 @@ ColorRGBA color_from_model_volume(const ModelVolume& model_volume)
 
     return color;
 }
-#else
-std::array<float, 4> color_from_model_volume(const ModelVolume& model_volume)
-{
-    std::array<float, 4> color;
-    if (model_volume.is_negative_volume()) {
-        color[0] = 0.2f;
-        color[1] = 0.2f;
-        color[2] = 0.2f;
-    }
-    else if (model_volume.is_modifier()) {
-        color[0] = 1.0f;
-        color[1] = 1.0f;
-        color[2] = 0.2f;
-    }
-    else if (model_volume.is_support_blocker()) {
-        color[0] = 1.0f;
-        color[1] = 0.2f;
-        color[2] = 0.2f;
-    }
-    else if (model_volume.is_support_enforcer()) {
-        color[0] = 0.2f;
-        color[1] = 0.2f;
-        color[2] = 1.0f;
-    }
-    color[3] = model_volume.is_model_part() ? 1.f : 0.5f;
-    return color;
-}
-#endif // ENABLE_COLOR_CLASSES
 
 Transform3d GLVolume::world_matrix() const
 {
@@ -673,13 +598,8 @@ int GLVolumeCollection::load_object_volume(
     const int            extruder_id  = model_volume->extruder_id();
     const ModelInstance *instance 	  = model_object->instances[instance_idx];
     const TriangleMesh  &mesh 		  = model_volume->mesh();
-#if ENABLE_COLOR_CLASSES
     ColorRGBA color = GLVolume::MODEL_COLOR[((color_by == "volume") ? volume_idx : obj_idx) % 4];
     color.a(model_volume->is_model_part() ? 1.0f : 0.5f);
-#else
-    std::array<float, 4> color = GLVolume::MODEL_COLOR[((color_by == "volume") ? volume_idx : obj_idx) % 4];
-    color[3] = model_volume->is_model_part() ? 1.f : 0.5f;
-#endif // ENABLE_COLOR_CLASSES
     this->volumes.emplace_back(new GLVolume(color));
     GLVolume& v = *this->volumes.back();
     v.set_color(color_from_model_volume(*model_volume));
@@ -760,22 +680,13 @@ int GLVolumeCollection::load_wipe_tower_preview(
         height = 0.1f;
 
     TriangleMesh mesh;
-#if ENABLE_COLOR_CLASSES
     ColorRGBA color = ColorRGBA::DARK_YELLOW();
-#else
-    std::array<float, 4> color = { 0.5f, 0.5f, 0.0f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
 
     // In case we don't know precise dimensions of the wipe tower yet, we'll draw
     // the box with different color with one side jagged:
     if (size_unknown) {
-#if ENABLE_COLOR_CLASSES
         color.r(0.9f);
         color.g(0.6f);
-#else
-        color[0] = 0.9f;
-        color[1] = 0.6f;
-#endif // ENABLE_COLOR_CLASSES
 
         // Too narrow tower would interfere with the teeth. The estimate is not precise anyway.
         depth = std::max(depth, 10.f);
@@ -831,22 +742,14 @@ int GLVolumeCollection::load_wipe_tower_preview(
     return int(volumes.size() - 1);
 }
 
-#if ENABLE_COLOR_CLASSES
 GLVolume* GLVolumeCollection::new_toolpath_volume(const ColorRGBA& rgba, size_t reserve_vbo_floats)
-#else
-GLVolume* GLVolumeCollection::new_toolpath_volume(const std::array<float, 4>& rgba, size_t reserve_vbo_floats)
-#endif // ENABLE_COLOR_CLASSES
 {
 	GLVolume *out = new_nontoolpath_volume(rgba, reserve_vbo_floats);
 	out->is_extrusion_path = true;
 	return out;
 }
 
-#if ENABLE_COLOR_CLASSES
 GLVolume* GLVolumeCollection::new_nontoolpath_volume(const ColorRGBA& rgba, size_t reserve_vbo_floats)
-#else
-GLVolume* GLVolumeCollection::new_nontoolpath_volume(const std::array<float, 4>& rgba, size_t reserve_vbo_floats)
-#endif // ENABLE_COLOR_CLASSES
 {
 	GLVolume *out = new GLVolume(rgba);
 	out->is_extrusion_path = false;
@@ -863,11 +766,7 @@ GLVolumeWithIdAndZList volumes_to_render(const GLVolumePtrs& volumes, GLVolumeCo
 
     for (unsigned int i = 0; i < (unsigned int)volumes.size(); ++i) {
         GLVolume* volume = volumes[i];
-#if ENABLE_COLOR_CLASSES
         bool is_transparent = volume->render_color.is_transparent();
-#else
-        bool is_transparent = (volume->render_color[3] < 1.0f);
-#endif // ENABLE_COLOR_CLASSES
         if (((type == GLVolumeCollection::ERenderType::Opaque && !is_transparent) ||
              (type == GLVolumeCollection::ERenderType::Transparent && is_transparent) ||
              type == GLVolumeCollection::ERenderType::All) &&
@@ -1046,8 +945,7 @@ bool GLVolumeCollection::check_outside_state(const BuildVolume &build_volume, Mo
 
 void GLVolumeCollection::reset_outside_state()
 {
-    for (GLVolume* volume : this->volumes)
-    {
+    for (GLVolume* volume : this->volumes) {
         if (volume != nullptr)
             volume->is_outside = false;
     }
@@ -1055,54 +953,17 @@ void GLVolumeCollection::reset_outside_state()
 
 void GLVolumeCollection::update_colors_by_extruder(const DynamicPrintConfig* config)
 {
-#if ENABLE_COLOR_CLASSES
     using ColorItem = std::pair<std::string, ColorRGBA>;
     std::vector<ColorItem> colors;
-#else
-    static const float inv_255 = 1.0f / 255.0f;
-
-    struct Color
-    {
-        std::string text;
-        unsigned char rgb[3];
-
-        Color()
-            : text("")
-        {
-            rgb[0] = 255;
-            rgb[1] = 255;
-            rgb[2] = 255;
-        }
-
-        void set(const std::string& text, unsigned char* rgb)
-        {
-            this->text = text;
-            ::memcpy((void*)this->rgb, (const void*)rgb, 3 * sizeof(unsigned char));
-        }
-    };
-
-    if (config == nullptr)
-        return;
-
-    unsigned char rgb[3];
-    std::vector<Color> colors;
-#endif // ENABLE_COLOR_CLASSES
 
     if (static_cast<PrinterTechnology>(config->opt_int("printer_technology")) == ptSLA) {
         const std::string& txt_color = config->opt_string("material_colour").empty() ? 
                                        print_config_def.get("material_colour")->get_default_value<ConfigOptionString>()->value : 
                                        config->opt_string("material_colour");
-#if ENABLE_COLOR_CLASSES
         ColorRGBA rgba;
         if (decode_color(txt_color, rgba))
             colors.push_back({ txt_color, rgba });
-#else
-        if (Slic3r::GUI::BitmapCache::parse_color(txt_color, rgb)) {
-            colors.resize(1);
-            colors[0].set(txt_color, rgb);
-        }
-#endif // ENABLE_COLOR_CLASSES
-    }
+}
     else {
         const ConfigOptionStrings* extruders_opt = dynamic_cast<const ConfigOptionStrings*>(config->option("extruder_colour"));
         if (extruders_opt == nullptr)
@@ -1118,7 +979,6 @@ void GLVolumeCollection::update_colors_by_extruder(const DynamicPrintConfig* con
         colors.resize(colors_count);
 
         for (unsigned int i = 0; i < colors_count; ++i) {
-#if ENABLE_COLOR_CLASSES
             const std::string& ext_color = config->opt_string("extruder_colour", i);
             ColorRGBA rgba;
             if (decode_color(ext_color, rgba))
@@ -1128,16 +988,6 @@ void GLVolumeCollection::update_colors_by_extruder(const DynamicPrintConfig* con
                 if (decode_color(fil_color, rgba))
                     colors[i] = { fil_color, rgba };
             }
-#else
-            const std::string& txt_color = config->opt_string("extruder_colour", i);
-            if (Slic3r::GUI::BitmapCache::parse_color(txt_color, rgb))
-                colors[i].set(txt_color, rgb);
-            else {
-                const std::string& txt_color = config->opt_string("filament_colour", i);
-                if (Slic3r::GUI::BitmapCache::parse_color(txt_color, rgb))
-                    colors[i].set(txt_color, rgb);
-            }
-#endif // ENABLE_COLOR_CLASSES
         }
     }
 
@@ -1149,18 +999,9 @@ void GLVolumeCollection::update_colors_by_extruder(const DynamicPrintConfig* con
         if (extruder_id < 0 || (int)colors.size() <= extruder_id)
             extruder_id = 0;
 
-#if ENABLE_COLOR_CLASSES
         const ColorItem& color = colors[extruder_id];
         if (!color.first.empty())
             volume->color = color.second;
-#else
-        const Color& color = colors[extruder_id];
-        if (!color.text.empty()) {
-            for (int i = 0; i < 3; ++i) {
-                volume->color[i] = (float)color.rgb[i] * inv_255;
-            }
-        }
-#endif // ENABLE_COLOR_CLASSES
     }
 }
 
diff --git a/src/slic3r/GUI/3DScene.hpp b/src/slic3r/GUI/3DScene.hpp
index 843ad256e..7ad12c354 100644
--- a/src/slic3r/GUI/3DScene.hpp
+++ b/src/slic3r/GUI/3DScene.hpp
@@ -7,9 +7,7 @@
 #include "libslic3r/TriangleMesh.hpp"
 #include "libslic3r/Utils.hpp"
 #include "libslic3r/Geometry.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include "GLModel.hpp"
 
@@ -46,11 +44,7 @@ class ModelVolume;
 enum ModelInstanceEPrintVolumeState : unsigned char;
 
 // Return appropriate color based on the ModelVolume.
-#if ENABLE_COLOR_CLASSES
 extern ColorRGBA color_from_model_volume(const ModelVolume& model_volume);
-#else
-std::array<float, 4> color_from_model_volume(const ModelVolume& model_volume);
-#endif // ENABLE_COLOR_CLASSES
 
 // A container for interleaved arrays of 3D vertices and normals,
 // possibly indexed by triangles and / or quads.
@@ -255,7 +249,6 @@ private:
 
 class GLVolume {
 public:
-#if ENABLE_COLOR_CLASSES
     static const ColorRGBA SELECTED_COLOR;
     static const ColorRGBA HOVER_SELECT_COLOR;
     static const ColorRGBA HOVER_DESELECT_COLOR;
@@ -266,18 +259,6 @@ public:
     static const ColorRGBA SLA_PAD_COLOR;
     static const ColorRGBA NEUTRAL_COLOR;
     static const std::array<ColorRGBA, 4> MODEL_COLOR;
-#else
-    static const std::array<float, 4> SELECTED_COLOR;
-    static const std::array<float, 4> HOVER_SELECT_COLOR;
-    static const std::array<float, 4> HOVER_DESELECT_COLOR;
-    static const std::array<float, 4> OUTSIDE_COLOR;
-    static const std::array<float, 4> SELECTED_OUTSIDE_COLOR;
-    static const std::array<float, 4> DISABLED_COLOR;
-    static const std::array<float, 4> SLA_SUPPORT_COLOR;
-    static const std::array<float, 4> SLA_PAD_COLOR;
-    static const std::array<float, 4> NEUTRAL_COLOR;
-    static const std::array<std::array<float, 4>, 4> MODEL_COLOR;
-#endif // ENABLE_COLOR_CLASSES
 
     enum EHoverState : unsigned char
     {
@@ -288,11 +269,7 @@ public:
     };
 
     GLVolume(float r = 1.0f, float g = 1.0f, float b = 1.0f, float a = 1.0f);
-#if ENABLE_COLOR_CLASSES
     GLVolume(const ColorRGBA& color) : GLVolume(color.r(), color.g(), color.b(), color.a()) {}
-#else
-    GLVolume(const std::array<float, 4>& rgba) : GLVolume(rgba[0], rgba[1], rgba[2], rgba[3]) {}
-#endif // ENABLE_COLOR_CLASSES
 
 private:
     Geometry::Transformation m_instance_transformation;
@@ -328,17 +305,10 @@ private:
     SinkingContours m_sinking_contours;
 
 public:
-#if ENABLE_COLOR_CLASSES
     // Color of the triangles / quads held by this volume.
     ColorRGBA color;
     // Color used to render this volume.
     ColorRGBA render_color;
-#else
-    // Color of the triangles / quads held by this volume.
-    std::array<float, 4> color;
-    // Color used to render this volume.
-    std::array<float, 4> render_color;
-#endif // ENABLE_COLOR_CLASSES
 
     struct CompositeID {
         CompositeID(int object_id, int volume_id, int instance_id) : object_id(object_id), volume_id(volume_id), instance_id(instance_id) {}
@@ -424,14 +394,8 @@ public:
         return out;
     }
 
-#if ENABLE_COLOR_CLASSES
     void set_color(const ColorRGBA& rgba)        { color = rgba; }
     void set_render_color(const ColorRGBA& rgba) { render_color = rgba; }
-#else
-    void set_color(const std::array<float, 4>& rgba);
-    void set_render_color(float r, float g, float b, float a);
-    void set_render_color(const std::array<float, 4>& rgba);
-#endif // ENABLE_COLOR_CLASSES
     // Sets render color in dependence of current state
     void set_render_color();
     // set color according to model volume
@@ -631,13 +595,8 @@ public:
     int load_wipe_tower_preview(
         int obj_idx, float pos_x, float pos_y, float width, float depth, float height, float rotation_angle, bool size_unknown, float brim_width, bool opengl_initialized);
 
-#if ENABLE_COLOR_CLASSES
     GLVolume* new_toolpath_volume(const ColorRGBA& rgba, size_t reserve_vbo_floats = 0);
     GLVolume* new_nontoolpath_volume(const ColorRGBA& rgba, size_t reserve_vbo_floats = 0);
-#else
-    GLVolume* new_toolpath_volume(const std::array<float, 4>& rgba, size_t reserve_vbo_floats = 0);
-    GLVolume* new_nontoolpath_volume(const std::array<float, 4>& rgba, size_t reserve_vbo_floats = 0);
-#endif // ENABLE_COLOR_CLASSES
 
     // Render the volumes by OpenGL.
     void render(ERenderType type, bool disable_cullface, const Transform3d& view_matrix, std::function<bool(const GLVolume&)> filter_func = std::function<bool(const GLVolume&)>()) const;
diff --git a/src/slic3r/GUI/AboutDialog.cpp b/src/slic3r/GUI/AboutDialog.cpp
index e28a6a799..e444fb03c 100644
--- a/src/slic3r/GUI/AboutDialog.cpp
+++ b/src/slic3r/GUI/AboutDialog.cpp
@@ -2,9 +2,7 @@
 #include "I18N.hpp"
 
 #include "libslic3r/Utils.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "GUI.hpp"
 #include "GUI_App.hpp"
 #include "MainFrame.hpp"
@@ -136,13 +134,8 @@ wxString CopyrightsDialog::get_html_text()
     wxColour bgr_clr = wxGetApp().get_window_default_clr();//wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW);
 
     const auto text_clr = wxGetApp().get_label_clr_default();
-#if ENABLE_COLOR_CLASSES
     const auto text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
     const auto bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
-#else
-    const auto text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-    const auto bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
 
     const wxString copyright_str = _L("Copyright") + "&copy; ";
     // TRN "Slic3r _is licensed under the_ License"
@@ -265,13 +258,8 @@ AboutDialog::AboutDialog()
         m_html->SetMinSize(wxSize(-1, 16 * wxGetApp().em_unit()));
         wxFont font = get_default_font(this);
         const auto text_clr = wxGetApp().get_label_clr_default();
-#if ENABLE_COLOR_CLASSES
         const auto text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
         const auto bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
-#else
-        auto text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-        auto bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
 
 		const int fs = font.GetPointSize()-1;
         int size[] = {fs,fs,fs,fs,fs,fs,fs};
diff --git a/src/slic3r/GUI/BitmapCache.cpp b/src/slic3r/GUI/BitmapCache.cpp
index 00516575b..e23591fb6 100644
--- a/src/slic3r/GUI/BitmapCache.cpp
+++ b/src/slic3r/GUI/BitmapCache.cpp
@@ -395,23 +395,5 @@ wxBitmap BitmapCache::mksolid(size_t width, size_t height, unsigned char r, unsi
     return wxImage_to_wxBitmap_with_alpha(std::move(image), scale);
 }
 
-#if !ENABLE_COLOR_CLASSES
-bool BitmapCache::parse_color(const std::string& scolor, unsigned char* rgb_out)
-{
-    rgb_out[0] = rgb_out[1] = rgb_out[2] = 0;
-    if (scolor.size() != 7 || scolor.front() != '#')
-        return false;
-    const char* c = scolor.data() + 1;
-    for (size_t i = 0; i < 3; ++i) {
-        int digit1 = hex_digit_to_int(*c++);
-        int digit2 = hex_digit_to_int(*c++);
-        if (digit1 == -1 || digit2 == -1)
-            return false;
-        rgb_out[i] = (unsigned char)(digit1 * 16 + digit2);
-    }
-    return true;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 } // namespace GUI
 } // namespace Slic3r
diff --git a/src/slic3r/GUI/BitmapCache.hpp b/src/slic3r/GUI/BitmapCache.hpp
index e2f5b6d31..5af90c5f7 100644
--- a/src/slic3r/GUI/BitmapCache.hpp
+++ b/src/slic3r/GUI/BitmapCache.hpp
@@ -9,9 +9,7 @@
     #include <wx/wx.h>
 #endif
 
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 struct NSVGimage;
 
@@ -48,17 +46,9 @@ public:
     wxBitmap* 		load_svg(const std::string &bitmap_key, unsigned width = 0, unsigned height = 0, const bool grayscale = false, const bool dark_mode = false, const std::string& new_color = "");
 
 	wxBitmap 		mksolid(size_t width, size_t height, unsigned char r, unsigned char g, unsigned char b, unsigned char transparency, bool suppress_scaling = false, size_t border_width = 0, bool dark_mode = false);
-#if ENABLE_COLOR_CLASSES
 	wxBitmap 		mksolid(size_t width, size_t height, const ColorRGB& rgb, bool suppress_scaling = false, size_t border_width = 0, bool dark_mode = false) { return mksolid(width, height, rgb.r_uchar(), rgb.g_uchar(), rgb.b_uchar(), wxALPHA_OPAQUE, suppress_scaling, border_width, dark_mode); }
-#else
-	wxBitmap 		mksolid(size_t width, size_t height, const unsigned char rgb[3], bool suppress_scaling = false, size_t border_width = 0, bool dark_mode = false) { return mksolid(width, height, rgb[0], rgb[1], rgb[2], wxALPHA_OPAQUE, suppress_scaling, border_width, dark_mode); }
-#endif // ENABLE_COLOR_CLASSES
 	wxBitmap 		mkclear(size_t width, size_t height) { return mksolid(width, height, 0, 0, 0, wxALPHA_TRANSPARENT); }
 
-#if !ENABLE_COLOR_CLASSES
-	static bool     parse_color(const std::string& scolor, unsigned char* rgb_out);
-#endif // !ENABLE_COLOR_CLASSES
-
 private:
     std::map<std::string, wxBitmap*>	m_map;
     double	m_gs	= 0.2;	// value, used for image.ConvertToGreyscale(m_gs, m_gs, m_gs)
diff --git a/src/slic3r/GUI/ConfigSnapshotDialog.cpp b/src/slic3r/GUI/ConfigSnapshotDialog.cpp
index 5772637f6..e2bea55d1 100644
--- a/src/slic3r/GUI/ConfigSnapshotDialog.cpp
+++ b/src/slic3r/GUI/ConfigSnapshotDialog.cpp
@@ -5,9 +5,7 @@
 
 #include "libslic3r/Utils.hpp"
 #include "libslic3r/Time.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "GUI_App.hpp"
 #include "MainFrame.hpp"
 #include "wxExtensions.hpp"
@@ -34,15 +32,9 @@ static wxString format_reason(const Config::Snapshot::Reason reason)
 
 static std::string get_color(wxColour colour) 
 {
-#if ENABLE_COLOR_CLASSES
     return encode_color(ColorRGB(colour.Red(), colour.Green(), colour.Blue()));
-#else
-    wxString clr_str = wxString::Format(wxT("#%02X%02X%02X"), colour.Red(), colour.Green(), colour.Blue());
-    return clr_str.ToStdString();
-#endif // ENABLE_COLOR_CLASSES
 };
 
-
 static wxString generate_html_row(const Config::Snapshot &snapshot, bool row_even, bool snapshot_active, bool dark_mode)
 {    
     // Start by declaring a row with an alternating background color.
diff --git a/src/slic3r/GUI/ConfigWizard.cpp b/src/slic3r/GUI/ConfigWizard.cpp
index 902e262eb..4ff089882 100644
--- a/src/slic3r/GUI/ConfigWizard.cpp
+++ b/src/slic3r/GUI/ConfigWizard.cpp
@@ -36,9 +36,7 @@
 #include "libslic3r/Config.hpp"
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Model.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "GUI.hpp"
 #include "GUI_App.hpp"
 #include "GUI_Utils.hpp"
@@ -749,15 +747,9 @@ void PageMaterials::set_compatible_printers_html_window(const std::vector<std::s
         wxSystemSettings::GetColour(wxSYS_COLOUR_MENU);
 #endif
 #endif
-#if ENABLE_COLOR_CLASSES
-    const auto text_clr = wxGetApp().get_label_clr_default();//wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOWTEXT);
+    const auto text_clr = wxGetApp().get_label_clr_default();
     const auto bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
     const auto text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
-#else
-    const auto bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-    const auto text_clr = wxGetApp().get_label_clr_default();
-    const auto text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
     wxString first_line = format_wxstr(_L("%1% marked with <b>*</b> are <b>not</b> compatible with some installed printers."), materials->technology == T_FFF ? _L("Filaments") : _L("SLA materials"));
     wxString text;
     if (all_printers) {
diff --git a/src/slic3r/GUI/DoubleSlider.cpp b/src/slic3r/GUI/DoubleSlider.cpp
index 12dc022dd..ee5aacb19 100644
--- a/src/slic3r/GUI/DoubleSlider.cpp
+++ b/src/slic3r/GUI/DoubleSlider.cpp
@@ -2557,7 +2557,6 @@ bool Control::check_ticks_changed_event(Type type)
 
 std::string TickCodeInfo::get_color_for_tick(TickCode tick, Type type, const int extruder)
 {
-#if ENABLE_COLOR_CLASSES
     auto opposite_one_color = [](const std::string& color) {
         ColorRGB rgb;
         decode_color(color, rgb);
@@ -2568,16 +2567,11 @@ std::string TickCodeInfo::get_color_for_tick(TickCode tick, Type type, const int
         ColorRGB rgb2; decode_color(b, rgb2);
         return encode_color(opposite(rgb1, rgb2));
     };
-#endif // ENABLE_COLOR_CLASSES
 
     if (mode == SingleExtruder && type == ColorChange && m_use_default_colors) {
 #if 1
         if (ticks.empty())
-#if ENABLE_COLOR_CLASSES
             return opposite_one_color((*m_colors)[0]);
-#else
-            return color_generator.get_opposite_color((*m_colors)[0]);
-#endif // ENABLE_COLOR_CLASSES
 
         auto before_tick_it = std::lower_bound(ticks.begin(), ticks.end(), tick);
         if (before_tick_it == ticks.end()) {
@@ -2585,40 +2579,24 @@ std::string TickCodeInfo::get_color_for_tick(TickCode tick, Type type, const int
                 if (--before_tick_it; before_tick_it->type == ColorChange)
                     break;
             if (before_tick_it->type == ColorChange)
-#if ENABLE_COLOR_CLASSES
                 return opposite_one_color(before_tick_it->color);
 
             return opposite_one_color((*m_colors)[0]);
-#else
-                return color_generator.get_opposite_color(before_tick_it->color);
-
-            return color_generator.get_opposite_color((*m_colors)[0]);
-#endif // ENABLE_COLOR_CLASSES
         }
 
         if (before_tick_it == ticks.begin()) {
             const std::string& frst_color = (*m_colors)[0];
             if (before_tick_it->type == ColorChange)
-#if ENABLE_COLOR_CLASSES
                 return opposite_two_colors(frst_color, before_tick_it->color);
-#else
-                return color_generator.get_opposite_color(frst_color, before_tick_it->color);
-#endif // ENABLE_COLOR_CLASSES
 
             auto next_tick_it = before_tick_it;
             while (next_tick_it != ticks.end())
                 if (++next_tick_it; next_tick_it->type == ColorChange)
                     break;
             if (next_tick_it->type == ColorChange)
-#if ENABLE_COLOR_CLASSES
                 return opposite_two_colors(frst_color, next_tick_it->color);
 
             return opposite_one_color(frst_color);
-#else
-                return color_generator.get_opposite_color(frst_color, next_tick_it->color);
-
-            return color_generator.get_opposite_color(frst_color);
-#endif // ENABLE_COLOR_CLASSES
         }
 
         std::string frst_color = "";
@@ -2639,27 +2617,15 @@ std::string TickCodeInfo::get_color_for_tick(TickCode tick, Type type, const int
 
         if (before_tick_it->type == ColorChange) {
             if (frst_color.empty())
-#if ENABLE_COLOR_CLASSES
                 return opposite_one_color(before_tick_it->color);
 
             return opposite_two_colors(before_tick_it->color, frst_color);
-#else
-                return color_generator.get_opposite_color(before_tick_it->color);
-
-            return color_generator.get_opposite_color(before_tick_it->color, frst_color);
-#endif // ENABLE_COLOR_CLASSES
         }
 
         if (frst_color.empty())
-#if ENABLE_COLOR_CLASSES
             return opposite_one_color((*m_colors)[0]);
 
         return opposite_two_colors((*m_colors)[0], frst_color);
-#else
-            return color_generator.get_opposite_color((*m_colors)[0]);
-
-        return color_generator.get_opposite_color((*m_colors)[0], frst_color);
-#endif // ENABLE_COLOR_CLASSES
 #else
         const std::vector<std::string>& colors = ColorPrintColors::get();
         if (ticks.empty())
diff --git a/src/slic3r/GUI/DoubleSlider.hpp b/src/slic3r/GUI/DoubleSlider.hpp
index 6783cd7e7..e0f713d87 100644
--- a/src/slic3r/GUI/DoubleSlider.hpp
+++ b/src/slic3r/GUI/DoubleSlider.hpp
@@ -3,9 +3,6 @@
 
 #include "libslic3r/CustomGCode.hpp"
 #include "wxExtensions.hpp"
-#if !ENABLE_COLOR_CLASSES
-#include "DoubleSlider_Utils.hpp"
-#endif // !ENABLE_COLOR_CLASSES
 
 #include <wx/window.h>
 #include <wx/control.h>
@@ -121,9 +118,6 @@ class TickCodeInfo
 //    int         m_default_color_idx = 0;
 
     std::vector<std::string>* m_colors {nullptr};
-#if !ENABLE_COLOR_CLASSES
-    ColorGenerator color_generator;
-#endif // !ENABLE_COLOR_CLASSES
 
     std::string get_color_for_tick(TickCode tick, Type type, const int extruder);
 
diff --git a/src/slic3r/GUI/DoubleSlider_Utils.hpp b/src/slic3r/GUI/DoubleSlider_Utils.hpp
index 83a9dae0b..283d527fa 100644
--- a/src/slic3r/GUI/DoubleSlider_Utils.hpp
+++ b/src/slic3r/GUI/DoubleSlider_Utils.hpp
@@ -4,196 +4,5 @@
 #include <stdio.h>
 #include <random>
 
-#if !ENABLE_COLOR_CLASSES
-
-#include "wx/colour.h"
-
-class ColorGenerator
-{
-    // Some of next code is borrowed from https://stackoverflow.com/questions/3018313/algorithm-to-convert-rgb-to-hsv-and-hsv-to-rgb-in-range-0-255-for-both
-    typedef struct {
-        double r;       // a fraction between 0 and 1
-        double g;       // a fraction between 0 and 1
-        double b;       // a fraction between 0 and 1
-    } rgb;
-
-    typedef struct {
-        double h;       // angle in degrees
-        double s;       // a fraction between 0 and 1
-        double v;       // a fraction between 0 and 1
-    } hsv;
-
-    //static hsv   rgb2hsv(rgb in);
-    //static rgb   hsv2rgb(hsv in);
-
-    hsv rgb2hsv(rgb in)
-    {
-        hsv         out;
-        double      min, max, delta;
-
-        min = in.r < in.g ? in.r : in.g;
-        min = min < in.b ? min : in.b;
-
-        max = in.r > in.g ? in.r : in.g;
-        max = max > in.b ? max : in.b;
-
-        out.v = max;                                // v
-        delta = max - min;
-        if (delta < 0.00001)
-        {
-            out.s = 0;
-            out.h = 0; // undefined, maybe nan?
-            return out;
-        }
-        if (max > 0.0) { // NOTE: if Max is == 0, this divide would cause a crash
-            out.s = (delta / max);                  // s
-        }
-        else {
-            // if max is 0, then r = g = b = 0              
-            // s = 0, h is undefined
-            out.s = 0.0;
-            out.h = NAN;                            // its now undefined
-            return out;
-        }
-        if (in.r >= max)                           // > is bogus, just keeps compilor happy
-            out.h = (in.g - in.b) / delta;        // between yellow & magenta
-        else
-            if (in.g >= max)
-                out.h = 2.0 + (in.b - in.r) / delta;  // between cyan & yellow
-            else
-                out.h = 4.0 + (in.r - in.g) / delta;  // between magenta & cyan
-
-        out.h *= 60.0;                              // degrees
-
-        if (out.h < 0.0)
-            out.h += 360.0;
-
-        return out;
-    }
-
-    hsv rgb2hsv(const std::string& str_clr_in)
-    {
-        wxColour clr(str_clr_in);
-        rgb in = { clr.Red() / 255.0, clr.Green() / 255.0, clr.Blue() / 255.0 };
-        return rgb2hsv(in);
-    }
-
-
-    rgb hsv2rgb(hsv in)
-    {
-        double      hh, p, q, t, ff;
-        long        i;
-        rgb         out;
-
-        if (in.s <= 0.0) {       // < is bogus, just shuts up warnings
-            out.r = in.v;
-            out.g = in.v;
-            out.b = in.v;
-            return out;
-        }
-        hh = in.h;
-        if (hh >= 360.0) hh -= 360.0;//hh = 0.0;
-        hh /= 60.0;
-        i = (long)hh;
-        ff = hh - i;
-        p = in.v * (1.0 - in.s);
-        q = in.v * (1.0 - (in.s * ff));
-        t = in.v * (1.0 - (in.s * (1.0 - ff)));
-
-        switch (i) {
-        case 0:
-            out.r = in.v;
-            out.g = t;
-            out.b = p;
-            break;
-        case 1:
-            out.r = q;
-            out.g = in.v;
-            out.b = p;
-            break;
-        case 2:
-            out.r = p;
-            out.g = in.v;
-            out.b = t;
-            break;
-
-        case 3:
-            out.r = p;
-            out.g = q;
-            out.b = in.v;
-            break;
-        case 4:
-            out.r = t;
-            out.g = p;
-            out.b = in.v;
-            break;
-        case 5:
-        default:
-            out.r = in.v;
-            out.g = p;
-            out.b = q;
-            break;
-        }
-        return out;
-    }
-
-    std::random_device rd;
-
-public:
-
-    ColorGenerator() {}
-    ~ColorGenerator() {}
-
-    double rand_val()
-    {
-        std::mt19937 rand_generator(rd());
-
-        // this value will be used for Saturation and Value
-        // to avoid extremely light/dark colors, take this value from range [0.65; 1.0]
-        std::uniform_real_distribution<double> distrib(0.65, 1.0);
-        return distrib(rand_generator);
-    }
-
-
-    std::string get_opposite_color(const std::string& color)
-    {
-        std::string opp_color = "";
-
-        hsv hsv_clr = rgb2hsv(color);
-        hsv_clr.h += 65; // 65 instead 60 to avoid circle values
-        hsv_clr.s = rand_val();
-        hsv_clr.v = rand_val();
-        rgb rgb_opp_color = hsv2rgb(hsv_clr);
-
-        wxString clr_str = wxString::Format(wxT("#%02X%02X%02X"), (unsigned char)(rgb_opp_color.r * 255), (unsigned char)(rgb_opp_color.g * 255), (unsigned char)(rgb_opp_color.b * 255));
-        opp_color = clr_str.ToStdString();
-
-        return opp_color;
-    }
-
-    std::string get_opposite_color(const std::string& color_frst, const std::string& color_scnd)
-    {
-        std::string opp_color = "";
-
-        hsv hsv_frst = rgb2hsv(color_frst);
-        hsv hsv_scnd = rgb2hsv(color_scnd);
-
-        double delta_h = fabs(hsv_frst.h - hsv_scnd.h);
-        double start_h = delta_h > 180 ? std::min<double>(hsv_scnd.h, hsv_frst.h) : std::max<double>(hsv_scnd.h, hsv_frst.h);
-        start_h += 5; // to avoid circle change of colors for 120 deg
-        if (delta_h < 180)
-            delta_h = 360 - delta_h;
-
-        hsv hsv_opp = hsv{ start_h + 0.5 * delta_h, rand_val(), rand_val() };
-        rgb rgb_opp_color = hsv2rgb(hsv_opp);
-
-        wxString clr_str = wxString::Format(wxT("#%02X%02X%02X"), (unsigned char)(rgb_opp_color.r * 255), (unsigned char)(rgb_opp_color.g * 255), (unsigned char)(rgb_opp_color.b * 255));
-        opp_color = clr_str.ToStdString();
-
-        return opp_color;
-    }
-};
-
-#endif // !ENABLE_COLOR_CLASSES
 
 #endif // slic3r_GUI_DoubleSlider_Utils_hpp_
diff --git a/src/slic3r/GUI/Field.cpp b/src/slic3r/GUI/Field.cpp
index 005cef8ec..172a07f66 100644
--- a/src/slic3r/GUI/Field.cpp
+++ b/src/slic3r/GUI/Field.cpp
@@ -1389,14 +1389,8 @@ boost::any& ColourPicker::get_value()
 	auto colour = static_cast<wxColourPickerCtrl*>(window)->GetColour();
     if (colour == wxTransparentColour)
         m_value = std::string("");
-    else {
-#if ENABLE_COLOR_CLASSES
+    else
         m_value = encode_color(ColorRGB(colour.Red(), colour.Green(), colour.Blue()));
-#else
-        auto clr_str = wxString::Format(wxT("#%02X%02X%02X"), colour.Red(), colour.Green(), colour.Blue());
-		m_value = clr_str.ToStdString();
-#endif // ENABLE_COLOR_CLASSES
-    }
 	return m_value;
 }
 
diff --git a/src/slic3r/GUI/GCodeViewer.cpp b/src/slic3r/GUI/GCodeViewer.cpp
index a1f090af7..9b413b4d6 100644
--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@@ -47,34 +47,6 @@ static EMoveType buffer_type(unsigned char id) {
     return static_cast<EMoveType>(static_cast<unsigned char>(EMoveType::Retract) + id);
 }
 
-#if !ENABLE_COLOR_CLASSES
-static std::array<float, 4> decode_color(const std::string& color) {
-    static const float INV_255 = 1.0f / 255.0f;
-
-    std::array<float, 4> ret = { 0.0f, 0.0f, 0.0f, 1.0f };
-    const char* c = color.data() + 1;
-    if (color.size() == 7 && color.front() == '#') {
-        for (size_t j = 0; j < 3; ++j) {
-            int digit1 = hex_digit_to_int(*c++);
-            int digit2 = hex_digit_to_int(*c++);
-            if (digit1 == -1 || digit2 == -1)
-                break;
-
-            ret[j] = float(digit1 * 16 + digit2) * INV_255;
-        }
-    }
-    return ret;
-}
-
-static std::vector<std::array<float, 4>> decode_colors(const std::vector<std::string>& colors) {
-    std::vector<std::array<float, 4>> output(colors.size(), { 0.0f, 0.0f, 0.0f, 1.0f });
-    for (size_t i = 0; i < colors.size(); ++i) {
-        output[i] = decode_color(colors[i]);
-    }
-    return output;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 // Round to a bin with minimum two digits resolution.
 // Equivalent to conversion to string with sprintf(buf, "%.2g", value) and conversion back to float, but faster.
 static float round_to_bin(const float value)
@@ -188,11 +160,7 @@ void GCodeViewer::TBuffer::add_path(const GCodeProcessorResult::MoveVertex& move
         move.volumetric_rate(), move.extruder_id, move.cp_color_id, { { endpoint, endpoint } } });
 }
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA GCodeViewer::Extrusions::Range::get_color_at(float value) const
-#else
-GCodeViewer::Color GCodeViewer::Extrusions::Range::get_color_at(float value) const
-#endif // ENABLE_COLOR_CLASSES
 {
     // Input value scaled to the colors range
     const float step = step_size();
@@ -204,20 +172,8 @@ GCodeViewer::Color GCodeViewer::Extrusions::Range::get_color_at(float value) con
     const size_t color_low_idx = std::clamp<size_t>(static_cast<size_t>(global_t), 0, color_max_idx);
     const size_t color_high_idx = std::clamp<size_t>(color_low_idx + 1, 0, color_max_idx);
 
-#if ENABLE_COLOR_CLASSES
     // Interpolate between the low and high colors to find exactly which color the input value should get
     return lerp(Range_Colors[color_low_idx], Range_Colors[color_high_idx], global_t - static_cast<float>(color_low_idx));
-#else
-    // Compute how far the value is between the low and high colors so that they can be interpolated
-    const float local_t = std::clamp(global_t - static_cast<float>(color_low_idx), 0.0f, 1.0f);
-
-    // Interpolate between the low and high colors to find exactly which color the input value should get
-    Color ret = { 0.0f, 0.0f, 0.0f, 1.0f };
-    for (unsigned int i = 0; i < 3; ++i) {
-        ret[i] = lerp(Range_Colors[color_low_idx][i], Range_Colors[color_high_idx][i], local_t);
-    }
-    return ret;
-#endif // ENABLE_COLOR_CLASSES
 }
 
 GCodeViewer::SequentialRangeCap::~SequentialRangeCap() {
@@ -491,11 +447,7 @@ void GCodeViewer::SequentialView::render(float legend_height) const
     gcode_window.render(legend_height, bottom, static_cast<uint64_t>(gcode_ids[current.last]));
 }
 
-#if ENABLE_COLOR_CLASSES
 const std::vector<ColorRGBA> GCodeViewer::Extrusion_Role_Colors{ {
-#else
-const std::vector<GCodeViewer::Color> GCodeViewer::Extrusion_Role_Colors {{
-#endif // ENABLE_COLOR_CLASSES
     { 0.90f, 0.70f, 0.70f, 1.0f },   // erNone
     { 1.00f, 0.90f, 0.30f, 1.0f },   // erPerimeter
     { 1.00f, 0.49f, 0.22f, 1.0f },   // erExternalPerimeter
@@ -514,11 +466,7 @@ const std::vector<GCodeViewer::Color> GCodeViewer::Extrusion_Role_Colors {{
     { 0.00f, 0.00f, 0.00f, 1.0f }    // erMixed
 }};
 
-#if ENABLE_COLOR_CLASSES
 const std::vector<ColorRGBA> GCodeViewer::Options_Colors{ {
-#else
-const std::vector<GCodeViewer::Color> GCodeViewer::Options_Colors {{
-#endif // ENABLE_COLOR_CLASSES
     { 0.803f, 0.135f, 0.839f, 1.0f },   // Retractions
     { 0.287f, 0.679f, 0.810f, 1.0f },   // Unretractions
     { 0.900f, 0.900f, 0.900f, 1.0f },   // Seams
@@ -528,11 +476,7 @@ const std::vector<GCodeViewer::Color> GCodeViewer::Options_Colors {{
     { 0.886f, 0.825f, 0.262f, 1.0f }    // CustomGCodes
 }};
 
-#if ENABLE_COLOR_CLASSES
 const std::vector<ColorRGBA> GCodeViewer::Travel_Colors{ {
-#else
-const std::vector<GCodeViewer::Color> GCodeViewer::Travel_Colors {{
-#endif // ENABLE_COLOR_CLASSES
     { 0.219f, 0.282f, 0.609f, 1.0f }, // Move
     { 0.112f, 0.422f, 0.103f, 1.0f }, // Extrude
     { 0.505f, 0.064f, 0.028f, 1.0f }  // Retract
@@ -540,11 +484,7 @@ const std::vector<GCodeViewer::Color> GCodeViewer::Travel_Colors {{
 
 #if 1
 // Normal ranges
-#if ENABLE_COLOR_CLASSES
 const std::vector<ColorRGBA> GCodeViewer::Range_Colors{ {
-#else
-const std::vector<GCodeViewer::Color> GCodeViewer::Range_Colors {{
-#endif // ENABLE_COLOR_CLASSES
     { 0.043f, 0.173f, 0.478f, 1.0f }, // bluish
     { 0.075f, 0.349f, 0.522f, 1.0f },
     { 0.110f, 0.533f, 0.569f, 1.0f },
@@ -559,11 +499,7 @@ const std::vector<GCodeViewer::Color> GCodeViewer::Range_Colors {{
 }};
 #else
 // Detailed ranges
-#if ENABLE_COLOR_CLASSES
 const std::vector<ColorRGBA> GCodeViewer::Range_Colors{ {
-#else
-const std::vector<GCodeViewer::Color> GCodeViewer::Range_Colors{ {
-#endif // ENABLE_COLOR_CLASSES
     { 0.043f, 0.173f, 0.478f, 1.0f }, // bluish
     { 0.5f * (0.043f + 0.075f), 0.5f * (0.173f + 0.349f), 0.5f * (0.478f + 0.522f), 1.0f },
     { 0.075f, 0.349f, 0.522f, 1.0f },
@@ -588,13 +524,8 @@ const std::vector<GCodeViewer::Color> GCodeViewer::Range_Colors{ {
 } };
 #endif
 
-#if ENABLE_COLOR_CLASSES
 const ColorRGBA GCodeViewer::Wipe_Color    = ColorRGBA::YELLOW();
 const ColorRGBA GCodeViewer::Neutral_Color = ColorRGBA::DARK_GRAY();
-#else
-const GCodeViewer::Color GCodeViewer::Wipe_Color = { 1.0f, 1.0f, 0.0f, 1.0f };
-const GCodeViewer::Color GCodeViewer::Neutral_Color = { 0.25f, 0.25f, 0.25f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
 
 GCodeViewer::GCodeViewer()
 {
@@ -765,31 +696,17 @@ void GCodeViewer::refresh(const GCodeProcessorResult& gcode_result, const std::v
 
     if (m_view_type == EViewType::Tool && !gcode_result.extruder_colors.empty())
         // update tool colors from config stored in the gcode
-#if ENABLE_COLOR_CLASSES
         decode_colors(gcode_result.extruder_colors, m_tool_colors);
-#else
-        m_tool_colors = decode_colors(gcode_result.extruder_colors);
-#endif // ENABLE_COLOR_CLASSES
     else
         // update tool colors
-#if ENABLE_COLOR_CLASSES
         decode_colors(str_tool_colors, m_tool_colors);
-#else
-        m_tool_colors = decode_colors(str_tool_colors);
-#endif // ENABLE_COLOR_CLASSES
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA default_color;
     decode_color("#FF8000", default_color);
-#endif // ENABLE_COLOR_CLASSES
 
     // ensure there are enough colors defined
     while (m_tool_colors.size() < std::max(size_t(1), gcode_result.extruders_count))
-#if ENABLE_COLOR_CLASSES
         m_tool_colors.push_back(default_color);
-#else
-        m_tool_colors.push_back(decode_color("#FF8000"));
-#endif // ENABLE_COLOR_CLASSES
 
     // update ranges for coloring / legend
     m_extrusions.reset_ranges();
@@ -853,11 +770,7 @@ void GCodeViewer::reset()
     m_paths_bounding_box = BoundingBoxf3();
     m_max_bounding_box = BoundingBoxf3();
     m_max_print_height = 0.0f;
-#if ENABLE_COLOR_CLASSES
     m_tool_colors = std::vector<ColorRGBA>();
-#else
-    m_tool_colors = std::vector<Color>();
-#endif // ENABLE_COLOR_CLASSES
     m_extruders_count = 0;
     m_extruder_ids = std::vector<unsigned char>();
     m_filament_diameters = std::vector<float>();
@@ -1035,11 +948,7 @@ void GCodeViewer::export_toolpaths_to_obj(const char* filename) const
         return;
 
     // collect color information to generate materials
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA> colors;
-#else
-    std::vector<Color> colors;
-#endif // ENABLE_COLOR_CLASSES
     for (const RenderPath& path : t_buffer.render_paths) {
         colors.push_back(path.color);
     }
@@ -1061,21 +970,12 @@ void GCodeViewer::export_toolpaths_to_obj(const char* filename) const
     fprintf(fp, "# Generated by %s-%s based on Slic3r\n", SLIC3R_APP_NAME, SLIC3R_VERSION);
 
     unsigned int colors_count = 1;
-#if ENABLE_COLOR_CLASSES
     for (const ColorRGBA& color : colors) {
         fprintf(fp, "\nnewmtl material_%d\n", colors_count++);
         fprintf(fp, "Ka 1 1 1\n");
         fprintf(fp, "Kd %g %g %g\n", color.r(), color.g(), color.b());
         fprintf(fp, "Ks 0 0 0\n");
     }
-#else
-    for (const Color& color : colors) {
-        fprintf(fp, "\nnewmtl material_%d\n", colors_count++);
-        fprintf(fp, "Ka 1 1 1\n");
-        fprintf(fp, "Kd %g %g %g\n", color[0], color[1], color[2]);
-        fprintf(fp, "Ks 0 0 0\n");
-    }
-#endif // ENABLE_COLOR_CLASSES
 
     fclose(fp);
 
@@ -1134,11 +1034,7 @@ void GCodeViewer::export_toolpaths_to_obj(const char* filename) const
     }
 
     size_t i = 0;
-#if ENABLE_COLOR_CLASSES
     for (const ColorRGBA& color : colors) {
-#else
-    for (const Color& color : colors) {
-#endif // ENABLE_COLOR_CLASSES
         // save material triangles to file
         fprintf(fp, "\nusemtl material_%zu\n", i + 1);
         fprintf(fp, "# triangles material %zu\n", i + 1);
@@ -2200,11 +2096,7 @@ void GCodeViewer::load_shells(const Print& print, bool initialized)
 
     for (GLVolume* volume : m_shells.volumes.volumes) {
         volume->zoom_to_volumes = false;
-#if ENABLE_COLOR_CLASSES
         volume->color.a(0.25f);
-#else
-        volume->color[3] = 0.25f;
-#endif // ENABLE_COLOR_CLASSES
         volume->force_native_color = true;
         volume->set_render_color();
     }
@@ -2217,11 +2109,7 @@ void GCodeViewer::refresh_render_paths(bool keep_sequential_current_first, bool
 #endif // ENABLE_GCODE_VIEWER_STATISTICS
 
     auto extrusion_color = [this](const Path& path) {
-#if ENABLE_COLOR_CLASSES
         ColorRGBA color;
-#else
-        Color color;
-#endif // ENABLE_COLOR_CLASSES
         switch (m_view_type)
         {
         case EViewType::FeatureType:    { color = Extrusion_Role_Colors[static_cast<unsigned int>(path.role)]; break; }
@@ -2234,21 +2122,13 @@ void GCodeViewer::refresh_render_paths(bool keep_sequential_current_first, bool
         case EViewType::Tool:           { color = m_tool_colors[path.extruder_id]; break; }
         case EViewType::ColorPrint:     {
             if (path.cp_color_id >= static_cast<unsigned char>(m_tool_colors.size()))
-#if ENABLE_COLOR_CLASSES
                 color = ColorRGBA::GRAY();
-#else
-                color = { 0.5f, 0.5f, 0.5f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
             else
                 color = m_tool_colors[path.cp_color_id];
 
             break;
         }
-#if ENABLE_COLOR_CLASSES
         default: { color = ColorRGBA::WHITE(); break; }
-#else
-        default: { color = { 1.0f, 1.0f, 1.0f, 1.0f }; break; }
-#endif // ENABLE_COLOR_CLASSES
         }
 
         return color;
@@ -2447,11 +2327,7 @@ void GCodeViewer::refresh_render_paths(bool keep_sequential_current_first, bool
         if (m_sequential_view.current.last < sub_path.first.s_id || sub_path.last.s_id < m_sequential_view.current.first)
             continue;
 
-#if ENABLE_COLOR_CLASSES
         ColorRGBA color;
-#else
-        Color color;
-#endif // ENABLE_COLOR_CLASSES
         switch (path.type)
         {
         case EMoveType::Tool_change:
@@ -3093,11 +2969,7 @@ void GCodeViewer::render_legend(float& legend_height)
 
     bool imperial_units = wxGetApp().app_config->get("use_inches") == "1";
 
-#if ENABLE_COLOR_CLASSES
     auto append_item = [icon_size, percent_bar_size, &imgui, imperial_units](EItemType type, const ColorRGBA& color, const std::string& label,
-#else
-    auto append_item = [icon_size, percent_bar_size, &imgui, imperial_units](EItemType type, const Color& color, const std::string& label,
-#endif // ENABLE_COLOR_CLASSES
         bool visible = true, const std::string& time = "", float percent = 0.0f, float max_percent = 0.0f, const std::array<float, 4>& offsets = { 0.0f, 0.0f, 0.0f, 0.0f },
         double used_filament_m = 0.0, double used_filament_g = 0.0,
         std::function<void()> callback = nullptr) {
@@ -3110,37 +2982,21 @@ void GCodeViewer::render_legend(float& legend_height)
         default:
         case EItemType::Rect: {
             draw_list->AddRectFilled({ pos.x + 1.0f, pos.y + 1.0f }, { pos.x + icon_size - 1.0f, pos.y + icon_size - 1.0f },
-#if ENABLE_COLOR_CLASSES
                 ImGuiWrapper::to_ImU32(color));
-#else
-                ImGui::GetColorU32({ color[0], color[1], color[2], 1.0f }));
-#endif // ENABLE_COLOR_CLASSES
             break;
         }
         case EItemType::Circle: {
             ImVec2 center(0.5f * (pos.x + pos.x + icon_size), 0.5f * (pos.y + pos.y + icon_size));
-#if ENABLE_COLOR_CLASSES
             draw_list->AddCircleFilled(center, 0.5f * icon_size, ImGuiWrapper::to_ImU32(color), 16);
-#else
-            draw_list->AddCircleFilled(center, 0.5f * icon_size, ImGui::GetColorU32({ color[0], color[1], color[2], 1.0f }), 16);
-#endif // ENABLE_COLOR_CLASSES
             break;
         }
         case EItemType::Hexagon: {
             ImVec2 center(0.5f * (pos.x + pos.x + icon_size), 0.5f * (pos.y + pos.y + icon_size));
-#if ENABLE_COLOR_CLASSES
             draw_list->AddNgonFilled(center, 0.5f * icon_size, ImGuiWrapper::to_ImU32(color), 6);
-#else
-            draw_list->AddNgonFilled(center, 0.5f * icon_size, ImGui::GetColorU32({ color[0], color[1], color[2], 1.0f }), 6);
-#endif // ENABLE_COLOR_CLASSES
             break;
         }
         case EItemType::Line: {
-#if ENABLE_COLOR_CLASSES
             draw_list->AddLine({ pos.x + 1, pos.y + icon_size - 1 }, { pos.x + icon_size - 1, pos.y + 1 }, ImGuiWrapper::to_ImU32(color), 3.0f);
-#else
-            draw_list->AddLine({ pos.x + 1, pos.y + icon_size - 1 }, { pos.x + icon_size - 1, pos.y + 1 }, ImGui::GetColorU32({ color[0], color[1], color[2], 1.0f }), 3.0f);
-#endif // ENABLE_COLOR_CLASSES
             break;
         }
         }
@@ -3258,11 +3114,7 @@ void GCodeViewer::render_legend(float& legend_height)
     };
 
     auto color_print_ranges = [this](unsigned char extruder_id, const std::vector<CustomGCode::Item>& custom_gcode_per_print_z) {
-#if ENABLE_COLOR_CLASSES
         std::vector<std::pair<ColorRGBA, std::pair<double, double>>> ret;
-#else
-        std::vector<std::pair<Color, std::pair<double, double>>> ret;
-#endif // ENABLE_COLOR_CLASSES
         ret.reserve(custom_gcode_per_print_z.size());
 
         for (const auto& item : custom_gcode_per_print_z) {
@@ -3281,16 +3133,11 @@ void GCodeViewer::render_legend(float& legend_height)
             const double previous_z = (lower_b == zs.begin()) ? 0.0 : *(--lower_b);
 
             // to avoid duplicate values, check adding values
-            if (ret.empty() || !(ret.back().second.first == previous_z && ret.back().second.second == current_z))
-#if ENABLE_COLOR_CLASSES
-            {
+            if (ret.empty() || !(ret.back().second.first == previous_z && ret.back().second.second == current_z)) {
                 ColorRGBA color;
                 decode_color(item.color, color);
                 ret.push_back({ color, { previous_z, current_z } });
             }
-#else
-                ret.push_back({ decode_color(item.color), { previous_z, current_z } });
-#endif // ENABLE_COLOR_CLASSES
         }
 
         return ret;
@@ -3485,15 +3332,10 @@ void GCodeViewer::render_legend(float& legend_height)
         if (need_scrollable)
             ImGui::BeginChild("color_prints", { -1.0f, child_height }, false);
         if (m_extruders_count == 1) { // single extruder use case
-#if ENABLE_COLOR_CLASSES
             const std::vector<std::pair<ColorRGBA, std::pair<double, double>>> cp_values = color_print_ranges(0, custom_gcode_per_print_z);
-#else
-            const std::vector<std::pair<Color, std::pair<double, double>>> cp_values = color_print_ranges(0, custom_gcode_per_print_z);
-#endif // ENABLE_COLOR_CLASSES
             const int items_cnt = static_cast<int>(cp_values.size());
-            if (items_cnt == 0) { // There are no color changes, but there are some pause print or custom Gcode
+            if (items_cnt == 0)  // There are no color changes, but there are some pause print or custom Gcode
                 append_item(EItemType::Rect, m_tool_colors.front(), _u8L("Default color"));
-            }
             else {
                 for (int i = items_cnt; i >= 0; --i) {
                     // create label for color change item
@@ -3512,11 +3354,7 @@ void GCodeViewer::render_legend(float& legend_height)
         else { // multi extruder use case
             // shows only extruders actually used
             for (unsigned char i : m_extruder_ids) {
-#if ENABLE_COLOR_CLASSES
                 const std::vector<std::pair<ColorRGBA, std::pair<double, double>>> cp_values = color_print_ranges(i, custom_gcode_per_print_z);
-#else
-                const std::vector<std::pair<Color, std::pair<double, double>>> cp_values = color_print_ranges(i, custom_gcode_per_print_z);
-#endif // ENABLE_COLOR_CLASSES
                 const int items_cnt = static_cast<int>(cp_values.size());
                 if (items_cnt == 0)
                     // There are no color changes, but there are some pause print or custom Gcode
@@ -3566,13 +3404,8 @@ void GCodeViewer::render_legend(float& legend_height)
             };
             EType type;
             int extruder_id;
-#if ENABLE_COLOR_CLASSES
             ColorRGBA color1;
             ColorRGBA color2;
-#else
-            Color color1;
-            Color color2;
-#endif // ENABLE_COLOR_CLASSES
             Times times;
             std::pair<double, double> used_filament{ 0.0f, 0.0f };
         };
@@ -3583,11 +3416,7 @@ void GCodeViewer::render_legend(float& legend_height)
 
             std::vector<CustomGCode::Item> custom_gcode_per_print_z = wxGetApp().is_editor() ? wxGetApp().plater()->model().custom_gcode_per_print_z.gcodes : m_custom_gcode_per_print_z;
             int extruders_count = wxGetApp().extruders_edited_cnt();
-#if ENABLE_COLOR_CLASSES
             std::vector<ColorRGBA> last_color(extruders_count);
-#else
-            std::vector<Color> last_color(extruders_count);
-#endif // ENABLE_COLOR_CLASSES
             for (int i = 0; i < extruders_count; ++i) {
                 last_color[i] = m_tool_colors[i];
             }
@@ -3599,13 +3428,8 @@ void GCodeViewer::render_legend(float& legend_height)
                 case CustomGCode::PausePrint: {
                     auto it = std::find_if(custom_gcode_per_print_z.begin(), custom_gcode_per_print_z.end(), [time_rec](const CustomGCode::Item& item) { return item.type == time_rec.first; });
                     if (it != custom_gcode_per_print_z.end()) {
-#if ENABLE_COLOR_CLASSES
                         items.push_back({ PartialTime::EType::Print, it->extruder, last_color[it->extruder - 1], ColorRGBA::BLACK(), time_rec.second });
                         items.push_back({ PartialTime::EType::Pause, it->extruder, ColorRGBA::BLACK(), ColorRGBA::BLACK(), time_rec.second });
-#else
-                        items.push_back({ PartialTime::EType::Print, it->extruder, last_color[it->extruder - 1], Color(), time_rec.second });
-                        items.push_back({ PartialTime::EType::Pause, it->extruder, Color(), Color(), time_rec.second });
-#endif // ENABLE_COLOR_CLASSES
                         custom_gcode_per_print_z.erase(it);
                     }
                     break;
@@ -3613,26 +3437,16 @@ void GCodeViewer::render_legend(float& legend_height)
                 case CustomGCode::ColorChange: {
                     auto it = std::find_if(custom_gcode_per_print_z.begin(), custom_gcode_per_print_z.end(), [time_rec](const CustomGCode::Item& item) { return item.type == time_rec.first; });
                     if (it != custom_gcode_per_print_z.end()) {
-#if ENABLE_COLOR_CLASSES
                         items.push_back({ PartialTime::EType::Print, it->extruder, last_color[it->extruder - 1], ColorRGBA::BLACK(), time_rec.second, get_used_filament_from_volume(used_filaments[color_change_idx++], it->extruder - 1) });
                         ColorRGBA color;
                         decode_color(it->color, color);
                         items.push_back({ PartialTime::EType::ColorChange, it->extruder, last_color[it->extruder - 1], color, time_rec.second });
                         last_color[it->extruder - 1] = color;
-#else
-                        items.push_back({ PartialTime::EType::Print, it->extruder, last_color[it->extruder - 1], Color(), time_rec.second, get_used_filament_from_volume(used_filaments[color_change_idx++], it->extruder-1) });
-                        items.push_back({ PartialTime::EType::ColorChange, it->extruder, last_color[it->extruder - 1], decode_color(it->color), time_rec.second });
-                        last_color[it->extruder - 1] = decode_color(it->color);
-#endif //  ENABLE_COLOR_CLASSES
                         last_extruder_id = it->extruder;
                         custom_gcode_per_print_z.erase(it);
                     }
                     else
-#if ENABLE_COLOR_CLASSES
                         items.push_back({ PartialTime::EType::Print, last_extruder_id, last_color[last_extruder_id - 1], ColorRGBA::BLACK(), time_rec.second, get_used_filament_from_volume(used_filaments[color_change_idx++], last_extruder_id - 1) });
-#else
-                        items.push_back({ PartialTime::EType::Print, last_extruder_id, last_color[last_extruder_id - 1], Color(), time_rec.second, get_used_filament_from_volume(used_filaments[color_change_idx++], last_extruder_id -1) });
-#endif // ENABLE_COLOR_CLASSES
 
                     break;
                 }
@@ -3643,11 +3457,7 @@ void GCodeViewer::render_legend(float& legend_height)
             return items;
         };
 
-#if ENABLE_COLOR_CLASSES
         auto append_color_change = [&imgui](const ColorRGBA& color1, const ColorRGBA& color2, const std::array<float, 4>& offsets, const Times& times) {
-#else
-        auto append_color_change = [&imgui](const Color& color1, const Color& color2, const std::array<float, 4>& offsets, const Times& times) {
-#endif // ENABLE_COLOR_CLASSES
             imgui.text(_u8L("Color change"));
             ImGui::SameLine();
 
@@ -3657,28 +3467,16 @@ void GCodeViewer::render_legend(float& legend_height)
             pos.x -= 0.5f * ImGui::GetStyle().ItemSpacing.x;
 
             draw_list->AddRectFilled({ pos.x + 1.0f, pos.y + 1.0f }, { pos.x + icon_size - 1.0f, pos.y + icon_size - 1.0f },
-#if ENABLE_COLOR_CLASSES
                 ImGuiWrapper::to_ImU32(color1));
-#else
-                ImGui::GetColorU32({ color1[0], color1[1], color1[2], 1.0f }));
-#endif // ENABLE_COLOR_CLASSES
             pos.x += icon_size;
             draw_list->AddRectFilled({ pos.x + 1.0f, pos.y + 1.0f }, { pos.x + icon_size - 1.0f, pos.y + icon_size - 1.0f },
-#if ENABLE_COLOR_CLASSES
                 ImGuiWrapper::to_ImU32(color2));
-#else
-                ImGui::GetColorU32({ color2[0], color2[1], color2[2], 1.0f }));
-#endif // ENABLE_COLOR_CLASSES
 
             ImGui::SameLine(offsets[0]);
             imgui.text(short_time(get_time_dhms(times.second - times.first)));
         };
 
-#if ENABLE_COLOR_CLASSES
         auto append_print = [&imgui, imperial_units](const ColorRGBA& color, const std::array<float, 4>& offsets, const Times& times, std::pair<double, double> used_filament) {
-#else
-        auto append_print = [&imgui, imperial_units](const Color& color, const std::array<float, 4>& offsets, const Times& times, std::pair<double, double> used_filament) {
-#endif // ENABLE_COLOR_CLASSES
             imgui.text(_u8L("Print"));
             ImGui::SameLine();
 
@@ -3688,11 +3486,7 @@ void GCodeViewer::render_legend(float& legend_height)
             pos.x -= 0.5f * ImGui::GetStyle().ItemSpacing.x;
 
             draw_list->AddRectFilled({ pos.x + 1.0f, pos.y + 1.0f }, { pos.x + icon_size - 1.0f, pos.y + icon_size - 1.0f },
-#if ENABLE_COLOR_CLASSES
                 ImGuiWrapper::to_ImU32(color));
-#else
-                ImGui::GetColorU32({ color[0], color[1], color[2], 1.0f }));
-#endif // ENABLE_COLOR_CLASSES
 
             ImGui::SameLine(offsets[0]);
             imgui.text(short_time(get_time_dhms(times.second)));
@@ -4109,11 +3903,7 @@ void GCodeViewer::log_memory_used(const std::string& label, int64_t additional)
     }
 }
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA GCodeViewer::option_color(EMoveType move_type) const
-#else
-GCodeViewer::Color GCodeViewer::option_color(EMoveType move_type) const
-#endif // ENABLE_COLOR_CLASSES
 {
     switch (move_type)
     {
diff --git a/src/slic3r/GUI/GCodeViewer.hpp b/src/slic3r/GUI/GCodeViewer.hpp
index 3b5cd5fae..2a5974717 100644
--- a/src/slic3r/GUI/GCodeViewer.hpp
+++ b/src/slic3r/GUI/GCodeViewer.hpp
@@ -22,9 +22,6 @@ namespace GUI {
 class GCodeViewer
 {
     using IBufferType = unsigned short;
-#if !ENABLE_COLOR_CLASSES
-    using Color = std::array<float, 4>;
-#endif // !ENABLE_COLOR_CLASSES
     using VertexBuffer = std::vector<float>;
     using MultiVertexBuffer = std::vector<VertexBuffer>;
     using IndexBuffer = std::vector<IBufferType>;
@@ -33,21 +30,12 @@ class GCodeViewer
     using InstanceIdBuffer = std::vector<size_t>;
     using InstancesOffsets = std::vector<Vec3f>;
 
-#if ENABLE_COLOR_CLASSES
     static const std::vector<ColorRGBA> Extrusion_Role_Colors;
     static const std::vector<ColorRGBA> Options_Colors;
     static const std::vector<ColorRGBA> Travel_Colors;
     static const std::vector<ColorRGBA> Range_Colors;
     static const ColorRGBA              Wipe_Color;
     static const ColorRGBA              Neutral_Color;
-#else
-    static const std::vector<Color> Extrusion_Role_Colors;
-    static const std::vector<Color> Options_Colors;
-    static const std::vector<Color> Travel_Colors;
-    static const std::vector<Color> Range_Colors;
-    static const Color              Wipe_Color;
-    static const Color              Neutral_Color;
-#endif // ENABLE_COLOR_CLASSES
 
     enum class EOptionsColors : unsigned char
     {
@@ -132,11 +120,7 @@ class GCodeViewer
                 // vbo id
                 unsigned int vbo{ 0 };
                 // Color to apply to the instances
-#if ENABLE_COLOR_CLASSES
                 ColorRGBA color;
-#else
-                Color color;
-#endif // ENABLE_COLOR_CLASSES
             };
 
             std::vector<Range> ranges;
@@ -258,11 +242,7 @@ class GCodeViewer
         // Index of the parent tbuffer
         unsigned char               tbuffer_id;
         // Render path property
-#if ENABLE_COLOR_CLASSES
         ColorRGBA                   color;
-#else
-        Color                       color;
-#endif // ENABLE_COLOR_CLASSES
         // Index of the buffer in TBuffer::indices
         unsigned int                ibuffer_id;
         // Render path content
@@ -282,19 +262,10 @@ class GCodeViewer
         bool operator() (const RenderPath &l, const RenderPath &r) const {
             if (l.tbuffer_id < r.tbuffer_id)
                 return true;
-#if ENABLE_COLOR_CLASSES
             if (l.color < r.color)
                 return true;
             else if (l.color > r.color)
                 return false;
-#else
-            for (int i = 0; i < 3; ++i) {
-                if (l.color[i] < r.color[i])
-                    return true;
-                else if (l.color[i] > r.color[i])
-                    return false;
-            }
-#endif // ENABLE_COLOR_CLASSES
             return l.ibuffer_id < r.ibuffer_id;
         }
     };
@@ -325,11 +296,7 @@ class GCodeViewer
         struct Model
         {
             GLModel model;
-#if ENABLE_COLOR_CLASSES
             ColorRGBA color;
-#else
-            Color color;
-#endif // ENABLE_COLOR_CLASSES
             InstanceVBuffer instances;
             GLModel::InitializationData data;
 
@@ -429,11 +396,7 @@ class GCodeViewer
             void reset() { min = FLT_MAX; max = -FLT_MAX; count = 0; }
 
             float step_size() const { return (max - min) / (static_cast<float>(Range_Colors.size()) - 1.0f); }
-#if ENABLE_COLOR_CLASSES
             ColorRGBA get_color_at(float value) const;
-#else
-            Color get_color_at(float value) const;
-#endif // ENABLE_COLOR_CLASSES
         };
 
         struct Ranges
@@ -525,11 +488,7 @@ class GCodeViewer
         TBuffer* buffer{ nullptr };
         unsigned int ibo{ 0 };
         unsigned int vbo{ 0 };
-#if ENABLE_COLOR_CLASSES
         ColorRGBA color;
-#else
-        Color color;
-#endif // ENABLE_COLOR_CLASSES
 
         ~SequentialRangeCap();
         bool is_renderable() const { return buffer != nullptr; }
@@ -733,11 +692,7 @@ private:
     // bounding box of toolpaths + marker tools
     BoundingBoxf3 m_max_bounding_box;
     float m_max_print_height{ 0.0f };
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA> m_tool_colors;
-#else
-    std::vector<Color> m_tool_colors;
-#endif // ENABLE_COLOR_CLASSES
     Layers m_layers;
     std::array<unsigned int, 2> m_layers_z_range;
     std::vector<ExtrusionRole> m_roles;
@@ -832,11 +787,7 @@ private:
     }
     bool is_visible(const Path& path) const { return is_visible(path.role); }
     void log_memory_used(const std::string& label, int64_t additional = 0) const;
-#if ENABLE_COLOR_CLASSES
     ColorRGBA option_color(EMoveType move_type) const;
-#else
-    Color option_color(EMoveType move_type) const;
-#endif // ENABLE_COLOR_CLASSES
 };
 
 } // namespace GUI
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 23c4f33d8..e28b8e5ba 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -72,18 +72,10 @@
 
 static constexpr const float TRACKBALLSIZE = 0.8f;
 
-#if ENABLE_COLOR_CLASSES
 static const Slic3r::ColorRGB DEFAULT_BG_DARK_COLOR  = { 0.478f, 0.478f, 0.478f };
 static const Slic3r::ColorRGB DEFAULT_BG_LIGHT_COLOR = { 0.753f, 0.753f, 0.753f };
 static const Slic3r::ColorRGB ERROR_BG_DARK_COLOR    = { 0.478f, 0.192f, 0.039f };
 static const Slic3r::ColorRGB ERROR_BG_LIGHT_COLOR   = { 0.753f, 0.192f, 0.039f };
-#else
-static constexpr const float DEFAULT_BG_DARK_COLOR[3] = { 0.478f, 0.478f, 0.478f };
-static constexpr const float DEFAULT_BG_LIGHT_COLOR[3] = { 0.753f, 0.753f, 0.753f };
-static constexpr const float ERROR_BG_DARK_COLOR[3] = { 0.478f, 0.192f, 0.039f };
-static constexpr const float ERROR_BG_LIGHT_COLOR[3] = { 0.753f, 0.192f, 0.039f };
-//static constexpr const float AXES_COLOR[3][3] = { { 1.0f, 0.0f, 0.0f }, { 0.0f, 1.0f, 0.0f }, { 0.0f, 0.0f, 1.0f } };
-#endif // ENABLE_COLOR_CLASSES
 
 // Number of floats
 static constexpr const size_t MAX_VERTEX_BUFFER_SIZE     = 131072 * 6; // 3.15MB
@@ -856,13 +848,8 @@ void GLCanvas3D::SequentialPrintClearance::set_polygons(const Polygons& polygons
 
 void GLCanvas3D::SequentialPrintClearance::render()
 {
-#if ENABLE_COLOR_CLASSES
     const ColorRGBA FILL_COLOR    = { 1.0f, 0.0f, 0.0f, 0.5f };
     const ColorRGBA NO_FILL_COLOR = { 1.0f, 1.0f, 1.0f, 0.75f };
-#else
-    std::array<float, 4> FILL_COLOR = { 1.0f, 0.0f, 0.0f, 0.5f };
-    std::array<float, 4> NO_FILL_COLOR = { 1.0f, 1.0f, 1.0f, 0.75f };
-#endif // ENABLE_COLOR_CLASSES
 
     GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
     if (shader == nullptr)
@@ -4111,11 +4098,6 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
         return ret;
     };
 
-#if !ENABLE_COLOR_CLASSES
-    static const std::array<float, 4> orange = { 0.923f, 0.504f, 0.264f, 1.0f };
-    static const std::array<float, 4> gray   = { 0.64f, 0.64f, 0.64f, 1.0f };
-#endif // !ENABLE_COLOR_CLASSES
-
     GLVolumePtrs visible_volumes;
 
     for (GLVolume* vol : volumes.volumes) {
@@ -4170,11 +4152,7 @@ void GLCanvas3D::_render_thumbnail_internal(ThumbnailData& thumbnail_data, const
     shader->set_uniform("emission_factor", 0.0f);
 
     for (GLVolume* vol : visible_volumes) {
-#if ENABLE_COLOR_CLASSES
         shader->set_uniform("uniform_color", (vol->printable && !vol->is_outside) ? (current_printer_technology() == ptSLA ? vol->color : ColorRGBA::ORANGE()) : ColorRGBA::GRAY());
-#else
-        shader->set_uniform("uniform_color", (vol->printable && !vol->is_outside) ? (current_printer_technology() == ptSLA ? vol->color : orange) : gray);
-#endif // ENABLE_COLOR_CLASSES
         // the volume may have been deactivated by an active gizmo
         bool is_active = vol->is_active;
         vol->is_active = true;
@@ -4905,34 +4883,20 @@ void GLCanvas3D::_picking_pass()
         int volume_id = -1;
         int gizmo_id = -1;
 
-#if ENABLE_COLOR_CLASSES
         std::array<GLubyte, 4> color = { 0, 0, 0, 0 };
-#else
-        GLubyte color[4] = { 0, 0, 0, 0 };
-#endif // ENABLE_COLOR_CLASSES
         const Size& cnv_size = get_canvas_size();
         bool inside = 0 <= m_mouse.position(0) && m_mouse.position(0) < cnv_size.get_width() && 0 <= m_mouse.position(1) && m_mouse.position(1) < cnv_size.get_height();
         if (inside) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glReadPixels(m_mouse.position(0), cnv_size.get_height() - m_mouse.position.y() - 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, (void*)color.data()));
-#else
-            glsafe(::glReadPixels(m_mouse.position(0), cnv_size.get_height() - m_mouse.position(1) - 1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, (void*)color));
-#endif // ENABLE_COLOR_CLASSES
             if (picking_checksum_alpha_channel(color[0], color[1], color[2]) == color[3]) {
                 // Only non-interpolated colors are valid, those have their lowest three bits zeroed.
                 // we reserve color = (0,0,0) for occluders (as the printbed) 
                 // volumes' id are shifted by 1
                 // see: _render_volumes_for_picking()
-#if ENABLE_COLOR_CLASSES
                 unsigned int id = picking_encode(color[0], color[1], color[2]);
                 volume_id = id - 1;
                 // gizmos' id are instead properly encoded by the color
                 gizmo_id = id;
-#else
-                volume_id = color[0] + (color[1] << 8) + (color[2] << 16) - 1;
-                // gizmos' id are instead properly encoded by the color
-                gizmo_id = color[0] + (color[1] << 8) + (color[2] << 16);
-#endif // ENABLE_COLOR_CLASSES
             }
         }
         if (0 <= volume_id && volume_id < (int)m_volumes.volumes.size()) {
@@ -5048,27 +5012,11 @@ void GLCanvas3D::_render_background() const
     glsafe(::glDisable(GL_DEPTH_TEST));
 
     ::glBegin(GL_QUADS);
-#if ENABLE_COLOR_CLASSES
     ::glColor3fv(use_error_color ? ERROR_BG_DARK_COLOR.data(): DEFAULT_BG_DARK_COLOR.data());
-#else
-    if (use_error_color)
-        ::glColor3fv(ERROR_BG_DARK_COLOR);
-    else
-        ::glColor3fv(DEFAULT_BG_DARK_COLOR);
-#endif // ENABLE_COLOR_CLASSES
-
     ::glVertex2f(-1.0f, -1.0f);
     ::glVertex2f(1.0f, -1.0f);
 
-#if ENABLE_COLOR_CLASSES
     ::glColor3fv(use_error_color ? ERROR_BG_LIGHT_COLOR.data() : DEFAULT_BG_LIGHT_COLOR.data());
-#else
-    if (use_error_color)
-        ::glColor3fv(ERROR_BG_LIGHT_COLOR);
-    else
-        ::glColor3fv(DEFAULT_BG_LIGHT_COLOR);
-#endif // ENABLE_COLOR_CLASSES
-
     ::glVertex2f(1.0f, 1.0f);
     ::glVertex2f(-1.0f, 1.0f);
     glsafe(::glEnd());
@@ -5351,10 +5299,6 @@ void GLCanvas3D::_render_overlays()
 
 void GLCanvas3D::_render_volumes_for_picking() const
 {
-#if !ENABLE_COLOR_CLASSES
-    static const GLfloat INV_255 = 1.0f / 255.0f;
-#endif // !ENABLE_COLOR_CLASSES
-
     // do not cull backfaces to show broken geometry, if any
     glsafe(::glDisable(GL_CULL_FACE));
 
@@ -5369,17 +5313,8 @@ void GLCanvas3D::_render_volumes_for_picking() const
 		        // Object picking mode. Render the object with a color encoding the object index.
                 // we reserve color = (0,0,0) for occluders (as the printbed) 
                 // so we shift volumes' id by 1 to get the proper color
-#if ENABLE_COLOR_CLASSES
                 const unsigned int id = 1 + volume.second.first;
                 glsafe(::glColor4fv(picking_decode(id).data()));
-#else
-                unsigned int id = 1 + volume.second.first;
-                unsigned int r = (id & (0x000000FF << 0)) << 0;
-		        unsigned int g = (id & (0x000000FF << 8)) >> 8;
-		        unsigned int b = (id & (0x000000FF << 16)) >> 16;
-		        unsigned int a = picking_checksum_alpha_channel(r, g, b);
-                glsafe(::glColor4f((GLfloat)r * INV_255, (GLfloat)g * INV_255, (GLfloat)b * INV_255, (GLfloat)a * INV_255));
-#endif // ENABLE_COLOR_CLASSES
                 volume.first->render();
 	        }
 	}
@@ -5799,11 +5734,7 @@ void GLCanvas3D::_load_print_toolpaths(const BuildVolume &build_volume)
     if (!print->has_skirt() && !print->has_brim())
         return;
 
-#if ENABLE_COLOR_CLASSES
     const ColorRGBA color = ColorRGBA::GREENISH();
-#else
-    const std::array<float, 4> color = { 0.5f, 1.0f, 0.5f, 1.0f }; // greenish
-#endif // ENABLE_COLOR_CLASSES
 
     // number of skirt layers
     size_t total_layer_count = 0;
@@ -5850,12 +5781,8 @@ void GLCanvas3D::_load_print_toolpaths(const BuildVolume &build_volume)
 
 void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, const BuildVolume& build_volume, const std::vector<std::string>& str_tool_colors, const std::vector<CustomGCode::Item>& color_print_values)
 {
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA> tool_colors;
     decode_colors(str_tool_colors, tool_colors);
-#else
-    std::vector<std::array<float, 4>> tool_colors = _parse_colors(str_tool_colors);
-#endif // ENABLE_COLOR_CLASSES
 
     struct Ctxt
     {
@@ -5864,35 +5791,20 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
         bool                         has_perimeters;
         bool                         has_infill;
         bool                         has_support;
-#if ENABLE_COLOR_CLASSES
         const std::vector<ColorRGBA>* tool_colors;
-#else
-        const std::vector<std::array<float, 4>>* tool_colors;
-#endif // ENABLE_COLOR_CLASSES
         bool                         is_single_material_print;
         int                          extruders_cnt;
         const std::vector<CustomGCode::Item>*   color_print_values;
 
-#if ENABLE_COLOR_CLASSES
         static ColorRGBA color_perimeters()           { return ColorRGBA::YELLOW(); }
         static ColorRGBA color_infill()               { return ColorRGBA::REDISH(); }
         static ColorRGBA color_support()              { return ColorRGBA::GREENISH(); }
         static ColorRGBA color_pause_or_custom_code() { return ColorRGBA::GRAY(); }
-#else
-        static const std::array<float, 4>& color_perimeters() { static std::array<float, 4> color = { 1.0f, 1.0f, 0.0f, 1.f }; return color; } // yellow
-        static const std::array<float, 4>& color_infill() { static std::array<float, 4> color = { 1.0f, 0.5f, 0.5f, 1.f }; return color; } // redish
-        static const std::array<float, 4>& color_support() { static std::array<float, 4> color = { 0.5f, 1.0f, 0.5f, 1.f }; return color; } // greenish
-        static const std::array<float, 4>& color_pause_or_custom_code() { static std::array<float, 4> color = { 0.5f, 0.5f, 0.5f, 1.f }; return color; } // gray
-#endif // ENABLE_COLOR_CLASSES
 
         // For cloring by a tool, return a parsed color.
         bool                         color_by_tool() const { return tool_colors != nullptr; }
         size_t                       number_tools() const { return color_by_tool() ? tool_colors->size() : 0; }
-#if ENABLE_COLOR_CLASSES
         const ColorRGBA&             color_tool(size_t tool) const { return (*tool_colors)[tool]; }
-#else
-        const std::array<float, 4>&  color_tool(size_t tool) const { return (*tool_colors)[tool]; }
-#endif // ENABLE_COLOR_CLASSES
 
         // For coloring by a color_print(M600), return a parsed color.
         bool                         color_by_color_print() const { return color_print_values!=nullptr; }
@@ -6032,11 +5944,7 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
     //FIXME Improve the heuristics for a grain size.
     size_t          grain_size = std::max(ctxt.layers.size() / 16, size_t(1));
     tbb::spin_mutex new_volume_mutex;
-#if ENABLE_COLOR_CLASSES
     auto            new_volume = [this, &new_volume_mutex](const ColorRGBA& color) {
-#else
-    auto            new_volume = [this, &new_volume_mutex](const std::array<float, 4>& color) {
-#endif // ENABLE_COLOR_CLASSES
         // Allocate the volume before locking.
 		GLVolume *volume = new GLVolume(color);
 		volume->is_extrusion_path = true;
@@ -6177,38 +6085,22 @@ void GLCanvas3D::_load_wipe_tower_toolpaths(const BuildVolume& build_volume, con
     if (!print->is_step_done(psWipeTower))
         return;
 
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA> tool_colors;
     decode_colors(str_tool_colors, tool_colors);
-#else
-    std::vector<std::array<float, 4>> tool_colors = _parse_colors(str_tool_colors);
-#endif // ENABLE_COLOR_CLASSES
 
     struct Ctxt
     {
         const Print                 *print;
-#if ENABLE_COLOR_CLASSES
         const std::vector<ColorRGBA>* tool_colors;
-#else
-        const std::vector<std::array<float, 4>>* tool_colors;
-#endif // ENABLE_COLOR_CLASSES
         Vec2f                        wipe_tower_pos;
         float                        wipe_tower_angle;
 
-#if ENABLE_COLOR_CLASSES
         static ColorRGBA color_support() { return ColorRGBA::GREENISH(); }
-#else
-        static const std::array<float, 4>& color_support() { static std::array<float, 4> color = { 0.5f, 1.0f, 0.5f, 1.f }; return color; } // greenish
-#endif // ENABLE_COLOR_CLASSES
 
         // For cloring by a tool, return a parsed color.
         bool                         color_by_tool() const { return tool_colors != nullptr; }
         size_t                       number_tools() const { return this->color_by_tool() ? tool_colors->size() : 0; }
-#if ENABLE_COLOR_CLASSES
         const ColorRGBA&             color_tool(size_t tool) const { return (*tool_colors)[tool]; }
-#else
-        const std::array<float, 4>&  color_tool(size_t tool) const { return (*tool_colors)[tool]; }
-#endif // ENABLE_COLOR_CLASSES
         int                          volume_idx(int tool, int feature) const {
             return this->color_by_tool() ? std::min<int>(this->number_tools() - 1, std::max<int>(tool, 0)) : feature;
         }
@@ -6240,11 +6132,7 @@ void GLCanvas3D::_load_wipe_tower_toolpaths(const BuildVolume& build_volume, con
     size_t          n_items = print->wipe_tower_data().tool_changes.size() + (ctxt.priming.empty() ? 0 : 1);
     size_t          grain_size = std::max(n_items / 128, size_t(1));
     tbb::spin_mutex new_volume_mutex;
-#if ENABLE_COLOR_CLASSES
     auto            new_volume = [this, &new_volume_mutex](const ColorRGBA& color) {
-#else
-    auto            new_volume = [this, &new_volume_mutex](const std::array<float, 4>& color) {
-#endif // ENABLE_COLOR_CLASSES
         auto *volume = new GLVolume(color);
 		volume->is_extrusion_path = true;
         tbb::spin_mutex::scoped_lock lock;
@@ -6363,11 +6251,7 @@ void GLCanvas3D::_load_sla_shells()
         return;
 
     auto add_volume = [this](const SLAPrintObject &object, int volume_id, const SLAPrintObject::Instance& instance,
-#if ENABLE_COLOR_CLASSES
         const TriangleMesh& mesh, const ColorRGBA& color, bool outside_printer_detection_enabled) {
-#else
-        const TriangleMesh& mesh, const std::array<float, 4>& color, bool outside_printer_detection_enabled) {
-#endif // ENABLE_COLOR_CLASSES
         m_volumes.volumes.emplace_back(new GLVolume(color));
         GLVolume& v = *m_volumes.volumes.back();
 #if ENABLE_SMOOTH_NORMALS
@@ -6429,30 +6313,6 @@ void GLCanvas3D::_set_warning_notification_if_needed(EWarning warning)
     _set_warning_notification(warning, show);
 }
 
-#if !ENABLE_COLOR_CLASSES
-std::vector<std::array<float, 4>> GLCanvas3D::_parse_colors(const std::vector<std::string>& colors)
-{
-    static const float INV_255 = 1.0f / 255.0f;
-
-    std::vector<std::array<float, 4>> output(colors.size(), { 1.0f, 1.0f, 1.0f, 1.0f });
-    for (size_t i = 0; i < colors.size(); ++i) {
-        const std::string& color = colors[i];
-        const char* c = color.data() + 1;
-        if (color.size() == 7 && color.front() == '#') {
-            for (size_t j = 0; j < 3; ++j) {
-                int digit1 = hex_digit_to_int(*c++);
-                int digit2 = hex_digit_to_int(*c++);
-                if (digit1 == -1 || digit2 == -1)
-                    break;
-
-                output[i][j] = float(digit1 * 16 + digit2) * INV_255;
-            }
-        }
-    }
-    return output;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 void GLCanvas3D::_set_warning_notification(EWarning warning, bool state)
 {
     enum ErrorType{
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index 1bae29d10..9e4815ac3 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -981,10 +981,6 @@ private:
     bool _deactivate_arrange_menu();
 
     float get_overlay_window_width() { return LayersEditing::get_overlay_window_width(); }
-
-#if !ENABLE_COLOR_CLASSES
-    static std::vector<std::array<float, 4>> _parse_colors(const std::vector<std::string>& colors);
-#endif // !ENABLE_COLOR_CLASSES
 };
 
 } // namespace GUI
diff --git a/src/slic3r/GUI/GLModel.cpp b/src/slic3r/GUI/GLModel.cpp
index f18cb0a23..fa804efc2 100644
--- a/src/slic3r/GUI/GLModel.cpp
+++ b/src/slic3r/GUI/GLModel.cpp
@@ -165,7 +165,6 @@ bool GLModel::init_from_file(const std::string& filename)
     return true;
 }
 
-#if ENABLE_COLOR_CLASSES
 void GLModel::set_color(int entity_id, const ColorRGBA& color)
 {
     for (size_t i = 0; i < m_render_data.size(); ++i) {
@@ -173,15 +172,6 @@ void GLModel::set_color(int entity_id, const ColorRGBA& color)
             m_render_data[i].color = color;
     }
 }
-#else
-void GLModel::set_color(int entity_id, const std::array<float, 4>& color)
-{
-    for (size_t i = 0; i < m_render_data.size(); ++i) {
-        if (entity_id == -1 || static_cast<int>(i) == entity_id)
-            m_render_data[i].color = color;
-    }
-}
-#endif // ENABLE_COLOR_CLASSES
 
 void GLModel::reset()
 {
@@ -226,11 +216,7 @@ void GLModel::render() const
         if (shader != nullptr)
             shader->set_uniform("uniform_color", data.color);
         else
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(data.color.data()));
-#else
-            glsafe(::glColor4fv(data.color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
         glsafe(::glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, data.ibo_id));
         glsafe(::glDrawElements(mode, static_cast<GLsizei>(data.indices_count), GL_UNSIGNED_INT, (const void*)0));
@@ -290,11 +276,7 @@ void GLModel::render_instanced(unsigned int instances_vbo, unsigned int instance
         if (shader != nullptr)
             shader->set_uniform("uniform_color", data.color);
         else
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(data.color.data()));
-#else
-            glsafe(::glColor4fv(data.color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
         glsafe(::glBindBuffer(GL_ARRAY_BUFFER, data.vbo_id));
         if (position_id != -1) {
diff --git a/src/slic3r/GUI/GLModel.hpp b/src/slic3r/GUI/GLModel.hpp
index 8bb60ba79..62722b18c 100644
--- a/src/slic3r/GUI/GLModel.hpp
+++ b/src/slic3r/GUI/GLModel.hpp
@@ -3,9 +3,7 @@
 
 #include "libslic3r/Point.hpp"
 #include "libslic3r/BoundingBox.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include <vector>
 #include <string>
 
@@ -36,11 +34,7 @@ namespace GUI {
             unsigned int vbo_id{ 0 };
             unsigned int ibo_id{ 0 };
             size_t indices_count{ 0 };
-#if ENABLE_COLOR_CLASSES
             ColorRGBA color;
-#else
-            std::array<float, 4> color{ 1.0f, 1.0f, 1.0f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
         };
 
         struct InitializationData
@@ -51,11 +45,7 @@ namespace GUI {
                 std::vector<Vec3f> positions;
                 std::vector<Vec3f> normals;
                 std::vector<unsigned int> indices;
-#if ENABLE_COLOR_CLASSES
                 ColorRGBA color;
-#else
-                std::array<float, 4> color{ 1.0f, 1.0f, 1.0f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
             };
 
             std::vector<Entity> entities;
@@ -85,11 +75,7 @@ namespace GUI {
         bool init_from_file(const std::string& filename);
 
         // if entity_id == -1 set the color of all entities
-#if ENABLE_COLOR_CLASSES
         void set_color(int entity_id, const ColorRGBA& color);
-#else
-        void set_color(int entity_id, const std::array<float, 4>& color);
-#endif // ENABLE_COLOR_CLASSES
 
         void reset();
         void render() const;
diff --git a/src/slic3r/GUI/GLShader.cpp b/src/slic3r/GUI/GLShader.cpp
index 42dcbeca0..32b3d5960 100644
--- a/src/slic3r/GUI/GLShader.cpp
+++ b/src/slic3r/GUI/GLShader.cpp
@@ -4,9 +4,7 @@
 #include "3DScene.hpp"
 #include "libslic3r/Utils.hpp"
 #include "libslic3r/format.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include <boost/nowide/fstream.hpp>
 #include <GL/glew.h>
@@ -309,7 +307,6 @@ void GLShaderProgram::set_uniform(int id, const Vec3d& value) const
     set_uniform(id, static_cast<Vec3f>(value.cast<float>()));
 }
 
-#if ENABLE_COLOR_CLASSES
 void GLShaderProgram::set_uniform(int id, const ColorRGB& value) const
 {
     set_uniform(id, value.data(), 3);
@@ -319,7 +316,6 @@ void GLShaderProgram::set_uniform(int id, const ColorRGBA& value) const
 {
     set_uniform(id, value.data(), 4);
 }
-#endif // ENABLE_COLOR_CLASSES
 
 int GLShaderProgram::get_attrib_location(const char* name) const
 {
diff --git a/src/slic3r/GUI/GLShader.hpp b/src/slic3r/GUI/GLShader.hpp
index 0a41461e2..06a5c00e5 100644
--- a/src/slic3r/GUI/GLShader.hpp
+++ b/src/slic3r/GUI/GLShader.hpp
@@ -9,10 +9,8 @@
 
 namespace Slic3r {
 
-#if ENABLE_COLOR_CLASSES
 class ColorRGB;
 class ColorRGBA;
-#endif // ENABLE_COLOR_CLASSES
 
 class GLShaderProgram
 {
@@ -65,10 +63,8 @@ public:
     void set_uniform(const char* name, const Matrix3f& value) const { set_uniform(get_uniform_location(name), value); }
     void set_uniform(const char* name, const Vec3f& value) const { set_uniform(get_uniform_location(name), value); }
     void set_uniform(const char* name, const Vec3d& value) const { set_uniform(get_uniform_location(name), value); }
-#if ENABLE_COLOR_CLASSES
     void set_uniform(const char* name, const ColorRGB& value) const { set_uniform(get_uniform_location(name), value); }
     void set_uniform(const char* name, const ColorRGBA& value) const { set_uniform(get_uniform_location(name), value); }
-#endif // ENABLE_COLOR_CLASSES
 
     void set_uniform(int id, int value) const;
     void set_uniform(int id, bool value) const;
@@ -86,10 +82,8 @@ public:
     void set_uniform(int id, const Matrix3f& value) const;
     void set_uniform(int id, const Vec3f& value) const;
     void set_uniform(int id, const Vec3d& value) const;
-#if ENABLE_COLOR_CLASSES
     void set_uniform(int id, const ColorRGB& value) const;
     void set_uniform(int id, const ColorRGBA& value) const;
-#endif // ENABLE_COLOR_CLASSES
 
     // returns -1 if not found
     int get_attrib_location(const char* name) const;
diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index 1834fcad5..93cd9073a 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -44,9 +44,7 @@
 #include "libslic3r/Model.hpp"
 #include "libslic3r/I18N.hpp"
 #include "libslic3r/PresetBundle.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include "GUI.hpp"
 #include "GUI_Utils.hpp"
@@ -1583,12 +1581,7 @@ void GUI_App::set_label_clr_modified(const wxColour& clr)
     if (m_color_label_modified == clr)
         return;
     m_color_label_modified = clr;
-#if ENABLE_COLOR_CLASSES
     const std::string str = encode_color(ColorRGB(clr.Red(), clr.Green(), clr.Blue()));
-#else
-    auto clr_str = wxString::Format(wxT("#%02X%02X%02X"), clr.Red(), clr.Green(), clr.Blue());
-    std::string str = clr_str.ToStdString();
-#endif // ENABLE_COLOR_CLASSES
     app_config->set("label_clr_modified", str);
     app_config->save();
 }
@@ -1598,12 +1591,7 @@ void GUI_App::set_label_clr_sys(const wxColour& clr)
     if (m_color_label_sys == clr)
         return;
     m_color_label_sys = clr;
-#if ENABLE_COLOR_CLASSES
     const std::string str = encode_color(ColorRGB(clr.Red(), clr.Green(), clr.Blue()));
-#else
-    auto clr_str = wxString::Format(wxT("#%02X%02X%02X"), clr.Red(), clr.Green(), clr.Blue());
-    std::string str = clr_str.ToStdString();
-#endif // ENABLE_COLOR_CLASSES
     app_config->set("label_clr_sys", str);
     app_config->save();
 }
diff --git a/src/slic3r/GUI/GUI_Utils.hpp b/src/slic3r/GUI/GUI_Utils.hpp
index 4b4bc2396..d7d3529fe 100644
--- a/src/slic3r/GUI/GUI_Utils.hpp
+++ b/src/slic3r/GUI/GUI_Utils.hpp
@@ -406,16 +406,6 @@ public:
 
 std::ostream& operator<<(std::ostream &os, const WindowMetrics& metrics);
 
-#if !ENABLE_COLOR_CLASSES
-inline int hex_digit_to_int(const char c)
-{
-    return
-        (c >= '0' && c <= '9') ? int(c - '0') :
-        (c >= 'A' && c <= 'F') ? int(c - 'A') + 10 :
-        (c >= 'a' && c <= 'f') ? int(c - 'a') + 10 : -1;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 class TaskTimer
 {
     std::chrono::milliseconds   start_timer;
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
index 3d697942c..21b5c13e6 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoBase.cpp
@@ -25,21 +25,9 @@ GLGizmoBase::Grabber::Grabber()
 
 void GLGizmoBase::Grabber::render(bool hover, float size) const
 {
-#if ENABLE_COLOR_CLASSES
     ColorRGBA render_color = color;
     if (hover)
         render_color = complementary(render_color);
-#else
-    std::array<float, 4> render_color;
-    if (hover) {
-        render_color[0] = (1.0f - color[0]);
-        render_color[1] = (1.0f - color[1]);
-        render_color[2] = (1.0f - color[2]);
-        render_color[3] = color[3];
-    }
-    else
-        render_color = color;
-#endif // ENABLE_COLOR_CLASSES
 
     render(size, render_color, false);
 }
@@ -54,11 +42,7 @@ float GLGizmoBase::Grabber::get_dragging_half_size(float size) const
     return get_half_size(size) * DraggingScaleFactor;
 }
 
-#if ENABLE_COLOR_CLASSES
 void GLGizmoBase::Grabber::render(float size, const ColorRGBA& render_color, bool picking) const
-#else
-void GLGizmoBase::Grabber::render(float size, const std::array<float, 4>& render_color, bool picking) const
-#endif // ENABLE_COLOR_CLASSES
 {
     if (!cube.is_initialized()) {
         // This cannot be done in constructor, OpenGL is not yet
@@ -109,13 +93,6 @@ void GLGizmoBase::set_hover_id(int id)
     }
 }
 
-#if !ENABLE_COLOR_CLASSES
-void GLGizmoBase::set_highlight_color(const std::array<float, 4>& color)
-{
-    m_highlight_color = color;
-}
-#endif // !ENABLE_COLOR_CLASSES
-
 void GLGizmoBase::enable_grabber(unsigned int id)
 {
     if (id < m_grabbers.size())
@@ -169,29 +146,13 @@ bool GLGizmoBase::update_items_state()
     return res;
 };
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA GLGizmoBase::picking_color_component(unsigned int id) const
 {
-#else
-std::array<float, 4> GLGizmoBase::picking_color_component(unsigned int id) const
-{
-    static const float INV_255 = 1.0f / 255.0f;
-#endif // ENABLE_COLOR_CLASSES
     id = BASE_ID - id;
     if (m_group_id > -1)
         id -= m_group_id;
 
-#if ENABLE_COLOR_CLASSES
     return picking_decode(id);
-#else
-    // color components are encoded to match the calculation of volume_id made into GLCanvas3D::_picking_pass()
-    return std::array<float, 4> { 
-		float((id >> 0) & 0xff) * INV_255, // red
-		float((id >> 8) & 0xff) * INV_255, // green
-		float((id >> 16) & 0xff) * INV_255, // blue
-		float(picking_checksum_alpha_channel(id & 0xff, (id >> 8) & 0xff, (id >> 16) & 0xff))* INV_255 // checksum for validating against unwanted alpha blending and multi sampling
-	};
-#endif // ENABLE_COLOR_CLASSES
 }
 
 void GLGizmoBase::render_grabbers(const BoundingBoxf3& box) const
@@ -219,12 +180,7 @@ void GLGizmoBase::render_grabbers_for_picking(const BoundingBoxf3& box) const
 
     for (unsigned int i = 0; i < (unsigned int)m_grabbers.size(); ++i) {
         if (m_grabbers[i].enabled) {
-#if ENABLE_COLOR_CLASSES
             m_grabbers[i].color = picking_color_component(i);
-#else
-            std::array<float, 4> color = picking_color_component(i);
-            m_grabbers[i].color = color;
-#endif // ENABLE_COLOR_CLASSES
             m_grabbers[i].render_for_picking(mean_size);
         }
     }
@@ -261,22 +217,6 @@ std::string GLGizmoBase::get_name(bool include_shortcut) const
     return out;
 }
 
-#if !ENABLE_COLOR_CLASSES
-// Produce an alpha channel checksum for the red green blue components. The alpha channel may then be used to verify, whether the rgb components
-// were not interpolated by alpha blending or multi sampling.
-unsigned char picking_checksum_alpha_channel(unsigned char red, unsigned char green, unsigned char blue)
-{
-	// 8 bit hash for the color
-	unsigned char b = ((((37 * red) + green) & 0x0ff) * 37 + blue) & 0x0ff;
-	// Increase enthropy by a bit reversal
-	b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
-	b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
-	b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
-	// Flip every second bit to increase the enthropy even more.
-	b ^= 0x55;
-	return b;
-}
-#endif // !ENABLE_COLOR_CLASSES
 
 } // namespace GUI
 } // namespace Slic3r
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoBase.hpp b/src/slic3r/GUI/Gizmos/GLGizmoBase.hpp
index ef0a91b3e..ca7e3f2f7 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoBase.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoBase.hpp
@@ -2,9 +2,7 @@
 #define slic3r_GLGizmoBase_hpp_
 
 #include "libslic3r/Point.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include "slic3r/GUI/I18N.hpp"
 #include "slic3r/GUI/GLModel.hpp"
@@ -21,23 +19,11 @@ class ModelObject;
 
 namespace GUI {
 
-#if ENABLE_COLOR_CLASSES
-    static const ColorRGBA DEFAULT_BASE_COLOR        = { 0.625f, 0.625f, 0.625f, 1.0f };
-    static const ColorRGBA DEFAULT_DRAG_COLOR        = ColorRGBA::WHITE();
-    static const ColorRGBA DEFAULT_HIGHLIGHT_COLOR   = ColorRGBA::ORANGE();
-    static const std::array<ColorRGBA, 3> AXES_COLOR = {{ ColorRGBA::X(), ColorRGBA::Y(), ColorRGBA::Z() }};
-    static const ColorRGBA CONSTRAINED_COLOR         = ColorRGBA::GRAY();
-#else
-static const std::array<float, 4> DEFAULT_BASE_COLOR = { 0.625f, 0.625f, 0.625f, 1.0f };
-static const std::array<float, 4> DEFAULT_DRAG_COLOR = { 1.0f, 1.0f, 1.0f, 1.0f };
-static const std::array<float, 4> DEFAULT_HIGHLIGHT_COLOR = { 1.0f, 0.38f, 0.0f, 1.0f };
-static const std::array<std::array<float, 4>, 3> AXES_COLOR = {{
-                                                                { 0.75f, 0.0f, 0.0f, 1.0f },
-                                                                { 0.0f, 0.75f, 0.0f, 1.0f },
-                                                                { 0.0f, 0.0f, 0.75f, 1.0f }
-                                                              }};
-static const std::array<float, 4> CONSTRAINED_COLOR = { 0.5f, 0.5f, 0.5f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
+static const ColorRGBA DEFAULT_BASE_COLOR        = { 0.625f, 0.625f, 0.625f, 1.0f };
+static const ColorRGBA DEFAULT_DRAG_COLOR        = ColorRGBA::WHITE();
+static const ColorRGBA DEFAULT_HIGHLIGHT_COLOR   = ColorRGBA::ORANGE();
+static const std::array<ColorRGBA, 3> AXES_COLOR = {{ ColorRGBA::X(), ColorRGBA::Y(), ColorRGBA::Z() }};
+static const ColorRGBA CONSTRAINED_COLOR         = ColorRGBA::GRAY();
 
 class ImGuiWrapper;
 class GLCanvas3D;
@@ -61,11 +47,7 @@ protected:
 
         Vec3d center;
         Vec3d angles;
-#if ENABLE_COLOR_CLASSES
         ColorRGBA color;
-#else
-        std::array<float, 4> color;
-#endif // ENABLE_COLOR_CLASSES
         bool enabled;
         bool dragging;
 
@@ -78,11 +60,7 @@ protected:
         float get_dragging_half_size(float size) const;
 
     private:
-#if ENABLE_COLOR_CLASSES
         void render(float size, const ColorRGBA& render_color, bool picking) const;
-#else
-        void render(float size, const std::array<float, 4>& render_color, bool picking) const;
-#endif // ENABLE_COLOR_CLASSES
 
         GLModel cube;
     };
@@ -115,15 +93,9 @@ protected:
     unsigned int m_sprite_id;
     int m_hover_id;
     bool m_dragging;
-#if ENABLE_COLOR_CLASSES
     ColorRGBA m_base_color;
     ColorRGBA m_drag_color;
     ColorRGBA m_highlight_color;
-#else
-    std::array<float, 4> m_base_color;
-    std::array<float, 4> m_drag_color;
-    std::array<float, 4> m_highlight_color;
-#endif // ENABLE_COLOR_CLASSES
     mutable std::vector<Grabber> m_grabbers;
     ImGuiWrapper* m_imgui;
     bool m_first_input_window_render;
@@ -167,11 +139,7 @@ public:
     int get_hover_id() const { return m_hover_id; }
     void set_hover_id(int id);
     
-#if ENABLE_COLOR_CLASSES
     void set_highlight_color(const ColorRGBA& color) { m_highlight_color = color; }
-#else
-    void set_highlight_color(const std::array<float, 4>& color);
-#endif // ENABLE_COLOR_CLASSES
 
     void enable_grabber(unsigned int id);
     void disable_grabber(unsigned int id);
@@ -213,11 +181,8 @@ protected:
 
     // Returns the picking color for the given id, based on the BASE_ID constant
     // No check is made for clashing with other picking color (i.e. GLVolumes)
-#if ENABLE_COLOR_CLASSES
     ColorRGBA picking_color_component(unsigned int id) const;
-#else
-    std::array<float, 4> picking_color_component(unsigned int id) const;
-#endif // ENABLE_COLOR_CLASSES
+
     void render_grabbers(const BoundingBoxf3& box) const;
     void render_grabbers(float size) const;
     void render_grabbers_for_picking(const BoundingBoxf3& box) const;
@@ -232,12 +197,6 @@ private:
     bool m_dirty;
 };
 
-#if !ENABLE_COLOR_CLASSES
-// Produce an alpha channel checksum for the red green blue components. The alpha channel may then be used to verify, whether the rgb components
-// were not interpolated by alpha blending or multi sampling.
-extern unsigned char picking_checksum_alpha_channel(unsigned char red, unsigned char green, unsigned char blue);
-#endif // !ENABLE_COLOR_CLASSES
-
 } // namespace GUI
 } // namespace Slic3r
 
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoCut.cpp b/src/slic3r/GUI/Gizmos/GLGizmoCut.cpp
index a06dd34a0..90e383e87 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoCut.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoCut.cpp
@@ -23,12 +23,8 @@ namespace GUI {
 
 const double GLGizmoCut::Offset = 10.0;
 const double GLGizmoCut::Margin = 20.0;
-#if ENABLE_COLOR_CLASSES
 static const ColorRGBA GRABBER_COLOR = ColorRGBA::ORANGE();
 static const ColorRGBA PLANE_COLOR   = { 0.8f, 0.8f, 0.8f, 0.5f };
-#else
-const std::array<float, 4> GLGizmoCut::GrabberColor = { 1.0, 0.5, 0.0, 1.0 };
-#endif // ENABLE_COLOR_CLASSES
 
 GLGizmoCut::GLGizmoCut(GLCanvas3D& parent, const std::string& icon_filename, unsigned int sprite_id)
     : GLGizmoBase(parent, icon_filename, sprite_id)
@@ -108,11 +104,7 @@ void GLGizmoCut::on_render()
 
     // Draw the cutting plane
     ::glBegin(GL_QUADS);
-#if ENABLE_COLOR_CLASSES
     ::glColor4fv(PLANE_COLOR.data());
-#else
-    ::glColor4f(0.8f, 0.8f, 0.8f, 0.5f);
-#endif // ENABLE_COLOR_CLASSES
     ::glVertex3f(min_x, min_y, plane_center.z());
     ::glVertex3f(max_x, min_y, plane_center.z());
     ::glVertex3f(max_x, max_y, plane_center.z());
@@ -143,11 +135,7 @@ void GLGizmoCut::on_render()
     shader->start_using();
     shader->set_uniform("emission_factor", 0.1f);
 
-#if ENABLE_COLOR_CLASSES
     m_grabbers[0].color = GRABBER_COLOR;
-#else
-    m_grabbers[0].color = GrabberColor;
-#endif // ENABLE_COLOR_CLASSES
     m_grabbers[0].render(m_hover_id == 0, (float)((box.size().x() + box.size().y() + box.size().z()) / 3.0));
 
     shader->stop_using();
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp b/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
index fde5d71b9..44291a409 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoCut.hpp
@@ -13,9 +13,6 @@ class GLGizmoCut : public GLGizmoBase
 {
     static const double Offset;
     static const double Margin;
-#if !ENABLE_COLOR_CLASSES
-    static const std::array<float, 4> GrabberColor;
-#endif // !ENABLE_COLOR_CLASSES
 
     double m_cut_z{ 0.0 };
     double m_max_z{ 0.0 };
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
index a29079ad4..fd32c68fc 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoFlatten.cpp
@@ -13,10 +13,8 @@
 namespace Slic3r {
 namespace GUI {
 
-#if ENABLE_COLOR_CLASSES
 static const Slic3r::ColorRGBA DEFAULT_PLANE_COLOR       = { 0.9f, 0.9f, 0.9f, 0.5f };
 static const Slic3r::ColorRGBA DEFAULT_HOVER_PLANE_COLOR = { 0.9f, 0.9f, 0.9f, 0.75f };
-#endif // ENABLE_COLOR_CLASSES
 
 GLGizmoFlatten::GLGizmoFlatten(GLCanvas3D& parent, const std::string& icon_filename, unsigned int sprite_id)
     : GLGizmoBase(parent, icon_filename, sprite_id)
@@ -78,15 +76,7 @@ void GLGizmoFlatten::on_render()
         if (this->is_plane_update_necessary())
             update_planes();
         for (int i = 0; i < (int)m_planes.size(); ++i) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(i == m_hover_id ? DEFAULT_HOVER_PLANE_COLOR.data() : DEFAULT_PLANE_COLOR.data()));
-#else
-            if (i == m_hover_id)
-                glsafe(::glColor4f(0.9f, 0.9f, 0.9f, 0.75f));
-            else
-                glsafe(::glColor4f(0.9f, 0.9f, 0.9f, 0.5f));
-#endif // ENABLE_COLOR_CLASSES
-
             if (m_planes[i].vbo.has_VBOs())
                 m_planes[i].vbo.render();
         }
@@ -112,11 +102,7 @@ void GLGizmoFlatten::on_render_for_picking()
         if (this->is_plane_update_necessary())
             update_planes();
         for (int i = 0; i < (int)m_planes.size(); ++i) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(picking_color_component(i).data()));
-#else
-            glsafe(::glColor4fv(picking_color_component(i).data()));
-#endif // ENABLE_COLOR_CLASSES
             m_planes[i].vbo.render();
         }
         glsafe(::glPopMatrix());
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp b/src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp
index 0f859aee2..16e3730b2 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoHollow.cpp
@@ -116,11 +116,7 @@ void GLGizmoHollow::render_points(const Selection& selection, bool picking) cons
     glsafe(::glTranslated(0.0, 0.0, m_c->selection_info()->get_sla_shift()));
     glsafe(::glMultMatrixd(instance_matrix.data()));
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA render_color;
-#else
-    std::array<float, 4> render_color;
-#endif // ENABLE_COLOR_CLASSES
     const sla::DrainHoles& drain_holes = m_c->selection_info()->model_object()->sla_drain_holes;
     size_t cache_size = drain_holes.size();
 
@@ -132,14 +128,8 @@ void GLGizmoHollow::render_points(const Selection& selection, bool picking) cons
             continue;
 
         // First decide about the color of the point.
-        if (picking) {
-#if ENABLE_COLOR_CLASSES
+        if (picking)
             render_color = picking_color_component(i);
-#else
-            std::array<float, 4> color = picking_color_component(i);
-            render_color = color;
-#endif // ENABLE_COLOR_CLASSES
-        }
         else {
             if (size_t(m_hover_id) == i)
                 render_color = {0.0f, 1.0f, 1.0f, 1.0f};
@@ -148,16 +138,8 @@ void GLGizmoHollow::render_points(const Selection& selection, bool picking) cons
                        m_c->hollowed_mesh()->get_drainholes()[i].failed) {
                 render_color = {1.0f, 0.0f, 0.0f, 0.5f};
             }
-            else { // neither hover nor picking
-#if ENABLE_COLOR_CLASSES
+            else  // neither hover nor picking
                 render_color = point_selected ? ColorRGBA(1.0f, 0.3f, 0.3f, 0.5f) : ColorRGBA(1.0f, 1.0f, 1.0f, 0.5f);
-#else
-                render_color[0] = point_selected ? 1.0f : 1.f;
-                render_color[1] = point_selected ? 0.3f : 1.f;
-                render_color[2] = point_selected ? 0.3f : 1.f;
-                render_color[3] = 0.5f;
-#endif // ENABLE_COLOR_CLASSES
-            }
         }
 
         const_cast<GLModel*>(&m_cylinder)->set_color(-1, render_color);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
index 6cc9b078a..f25a65020 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.cpp
@@ -56,29 +56,12 @@ bool GLGizmoMmuSegmentation::on_is_activable() const
     return GLGizmoPainterBase::on_is_activable() && wxGetApp().extruders_edited_cnt() > 1;
 }
 
-#if ENABLE_COLOR_CLASSES
 static std::vector<ColorRGBA> get_extruders_colors()
 {
-#else
-static std::vector<std::array<float, 4>> get_extruders_colors()
-{
-    unsigned char                     rgb_color[3] = {};
-#endif // ENABLE_COLOR_CLASSES
     std::vector<std::string> colors = Slic3r::GUI::wxGetApp().plater()->get_extruder_colors_from_plater_config();
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA> ret;
     decode_colors(colors, ret);
     return ret;
-#else
-    std::vector<std::array<float, 4>> colors_out(colors.size());
-    for (const std::string &color : colors) {
-        Slic3r::GUI::BitmapCache::parse_color(color, rgb_color);
-        size_t color_idx      = &color - &colors.front();
-        colors_out[color_idx] = {float(rgb_color[0]) / 255.f, float(rgb_color[1]) / 255.f, float(rgb_color[2]) / 255.f, 1.f};
-    }
-
-    return colors_out;
-#endif // ENABLE_COLOR_CLASSES
 }
 
 static std::vector<std::string> get_extruders_names()
@@ -223,27 +206,14 @@ void GLGizmoMmuSegmentation::render_triangles(const Selection &selection) const
     }
 }
 
-#if ENABLE_COLOR_CLASSES
 static void render_extruders_combo(const std::string& label,
                                    const std::vector<std::string>& extruders,
                                    const std::vector<ColorRGBA>& extruders_colors,
                                    size_t& selection_idx)
-#else
-static void render_extruders_combo(const std::string                       &label,
-                                   const std::vector<std::string>          &extruders,
-                                   const std::vector<std::array<float, 4>> &extruders_colors,
-                                   size_t                                  &selection_idx)
-#endif // ENABLE_COLOR_CLASSES
 {
     assert(!extruders_colors.empty());
     assert(extruders_colors.size() == extruders_colors.size());
 
-#if !ENABLE_COLOR_CLASSES
-    auto convert_to_imu32 = [](const std::array<float, 4> &color) -> ImU32 {
-        return IM_COL32(uint8_t(color[0] * 255.f), uint8_t(color[1] * 255.f), uint8_t(color[2] * 255.f), uint8_t(color[3] * 255.f));
-    };
-#endif // !ENABLE_COLOR_CLASSES
-
     size_t selection_out = selection_idx;
     // It is necessary to use BeginGroup(). Otherwise, when using SameLine() is called, then other items will be drawn inside the combobox.
     ImGui::BeginGroup();
@@ -259,11 +229,7 @@ static void render_extruders_combo(const std::string                       &labe
             ImGui::SameLine();
             ImGuiStyle &style  = ImGui::GetStyle();
             float       height = ImGui::GetTextLineHeight();
-#if ENABLE_COLOR_CLASSES
             ImGui::GetWindowDrawList()->AddRectFilled(start_position, ImVec2(start_position.x + height + height / 2, start_position.y + height), ImGuiWrapper::to_ImU32(extruders_colors[extruder_idx]));
-#else
-            ImGui::GetWindowDrawList()->AddRectFilled(start_position, ImVec2(start_position.x + height + height / 2, start_position.y + height), convert_to_imu32(extruders_colors[extruder_idx]));
-#endif // ENABLE_COLOR_CLASSES
             ImGui::GetWindowDrawList()->AddRect(start_position, ImVec2(start_position.x + height + height / 2, start_position.y + height), IM_COL32_BLACK);
 
             ImGui::SetCursorScreenPos(ImVec2(start_position.x + height + height / 2 + style.FramePadding.x, start_position.y));
@@ -281,11 +247,7 @@ static void render_extruders_combo(const std::string                       &labe
     ImVec2 p      = ImGui::GetCursorScreenPos();
     float  height = ImGui::GetTextLineHeight();
 
-#if ENABLE_COLOR_CLASSES
     ImGui::GetWindowDrawList()->AddRectFilled(p, ImVec2(p.x + height + height / 2, p.y + height), ImGuiWrapper::to_ImU32(extruders_colors[selection_idx]));
-#else
-    ImGui::GetWindowDrawList()->AddRectFilled(p, ImVec2(p.x + height + height / 2, p.y + height), convert_to_imu32(extruders_colors[selection_idx]));
-#endif // ENABLE_COLOR_CLASSES
     ImGui::GetWindowDrawList()->AddRect(p, ImVec2(p.x + height + height / 2, p.y + height), IM_COL32_BLACK);
 
     ImGui::SetCursorScreenPos(ImVec2(p.x + height + height / 2 + style.FramePadding.x, p.y));
@@ -367,17 +329,10 @@ void GLGizmoMmuSegmentation::on_render_input_window(float x, float y, float bott
     render_extruders_combo("##first_color_combo", m_original_extruders_names, m_original_extruders_colors, m_first_selected_extruder_idx);
     ImGui::SameLine();
 
-#if ENABLE_COLOR_CLASSES
     const ColorRGBA& select_first_color = m_modified_extruders_colors[m_first_selected_extruder_idx];
     ImVec4           first_color        = ImGuiWrapper::to_ImVec4(select_first_color);
     if (ImGui::ColorEdit4("First color##color_picker", (float*)&first_color, ImGuiColorEditFlags_NoAlpha | ImGuiColorEditFlags_NoInputs | ImGuiColorEditFlags_NoLabel))
         m_modified_extruders_colors[m_first_selected_extruder_idx] = ImGuiWrapper::from_ImVec4(first_color);
-#else
-    const std::array<float, 4> &select_first_color = m_modified_extruders_colors[m_first_selected_extruder_idx];
-    ImVec4                      first_color = ImVec4(select_first_color[0], select_first_color[1], select_first_color[2], select_first_color[3]);
-    if (ImGui::ColorEdit4("First color##color_picker", (float*)&first_color, ImGuiColorEditFlags_NoAlpha | ImGuiColorEditFlags_NoInputs | ImGuiColorEditFlags_NoLabel))
-        m_modified_extruders_colors[m_first_selected_extruder_idx] = { first_color.x, first_color.y, first_color.z, first_color.w };
-#endif // ENABLE_COLOR_CLASSES
 
     ImGui::AlignTextToFramePadding();
     m_imgui->text(m_desc.at("second_color"));
@@ -386,17 +341,10 @@ void GLGizmoMmuSegmentation::on_render_input_window(float x, float y, float bott
     render_extruders_combo("##second_color_combo", m_original_extruders_names, m_original_extruders_colors, m_second_selected_extruder_idx);
     ImGui::SameLine();
 
-#if ENABLE_COLOR_CLASSES
     const ColorRGBA& select_second_color = m_modified_extruders_colors[m_second_selected_extruder_idx];
     ImVec4           second_color        = ImGuiWrapper::to_ImVec4(select_second_color);
     if (ImGui::ColorEdit4("Second color##color_picker", (float*)&second_color, ImGuiColorEditFlags_NoAlpha | ImGuiColorEditFlags_NoInputs | ImGuiColorEditFlags_NoLabel))
         m_modified_extruders_colors[m_second_selected_extruder_idx] = ImGuiWrapper::from_ImVec4(second_color);
-#else
-    const std::array<float, 4> &select_second_color = m_modified_extruders_colors[m_second_selected_extruder_idx];
-    ImVec4                      second_color        = ImVec4(select_second_color[0], select_second_color[1], select_second_color[2], select_second_color[3]);
-    if (ImGui::ColorEdit4("Second color##color_picker", (float*)&second_color, ImGuiColorEditFlags_NoAlpha | ImGuiColorEditFlags_NoInputs | ImGuiColorEditFlags_NoLabel))
-        m_modified_extruders_colors[m_second_selected_extruder_idx] = { second_color.x, second_color.y, second_color.z, second_color.w };
-#endif // ENABLE_COLOR_CLASSES
 
     const float max_tooltip_width = ImGui::GetFontSize() * 20.0f;
 
@@ -607,7 +555,6 @@ PainterGizmoType GLGizmoMmuSegmentation::get_painter_type() const
     return PainterGizmoType::MMU_SEGMENTATION;
 }
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA GLGizmoMmuSegmentation::get_cursor_sphere_left_button_color() const
 {
     ColorRGBA color = m_modified_extruders_colors[m_first_selected_extruder_idx];
@@ -621,19 +568,6 @@ ColorRGBA GLGizmoMmuSegmentation::get_cursor_sphere_right_button_color() const
     color.a(0.25f);
     return color;
 }
-#else
-std::array<float, 4> GLGizmoMmuSegmentation::get_cursor_sphere_left_button_color() const
-{
-    const std::array<float, 4> &color = m_modified_extruders_colors[m_first_selected_extruder_idx];
-    return {color[0], color[1], color[2], 0.25f};
-}
-
-std::array<float, 4> GLGizmoMmuSegmentation::get_cursor_sphere_right_button_color() const
-{
-    const std::array<float, 4> &color = m_modified_extruders_colors[m_second_selected_extruder_idx];
-    return {color[0], color[1], color[2], 0.25f};
-}
-#endif // ENABLE_COLOR_CLASSES
 
 void TriangleSelectorMmGui::render(ImGuiWrapper *imgui)
 {
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
index cde33d99c..70bb5241d 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMmuSegmentation.hpp
@@ -62,13 +62,8 @@ public:
 class TriangleSelectorMmGui : public TriangleSelectorGUI {
 public:
     // Plus 1 in the initialization of m_gizmo_scene is because the first position is allocated for non-painted triangles, and the indices above colors.size() are allocated for seed fill.
-#if ENABLE_COLOR_CLASSES
     TriangleSelectorMmGui(const TriangleMesh& mesh, const std::vector<ColorRGBA>& colors, const ColorRGBA& default_volume_color)
         : TriangleSelectorGUI(mesh), m_colors(colors), m_default_volume_color(default_volume_color), m_gizmo_scene(2 * (colors.size() + 1)) {}
-#else
-    explicit TriangleSelectorMmGui(const TriangleMesh &mesh, const std::vector<std::array<float, 4>> &colors, const std::array<float, 4> &default_volume_color)
-        : TriangleSelectorGUI(mesh), m_colors(colors), m_default_volume_color(default_volume_color), m_gizmo_scene(2 * (colors.size() + 1)) {}
-#endif // ENABLE_COLOR_CLASSES
     ~TriangleSelectorMmGui() override = default;
 
     // Render current selection. Transformation matrices are supposed
@@ -78,13 +73,8 @@ public:
 private:
     void update_render_data();
 
-#if ENABLE_COLOR_CLASSES
     const std::vector<ColorRGBA>&            m_colors;
     const ColorRGBA                          m_default_volume_color;
-#else
-    const std::vector<std::array<float, 4>> &m_colors;
-    const std::array<float, 4>               m_default_volume_color;
-#endif // ENABLE_COLOR_CLASSES
     GLMmSegmentationGizmo3DScene             m_gizmo_scene;
 };
 
@@ -110,13 +100,8 @@ public:
     const float get_cursor_radius_min() const override { return CursorRadiusMin; }
 
 protected:
-#if ENABLE_COLOR_CLASSES
     ColorRGBA get_cursor_sphere_left_button_color() const override;
     ColorRGBA get_cursor_sphere_right_button_color() const override;
-#else
-    std::array<float, 4> get_cursor_sphere_left_button_color() const override;
-    std::array<float, 4> get_cursor_sphere_right_button_color() const override;
-#endif // ENABLE_COLOR_CLASSES
 
     EnforcerBlockerType get_left_button_state_type() const override { return EnforcerBlockerType(m_first_selected_extruder_idx + 1); }
     EnforcerBlockerType get_right_button_state_type() const override { return EnforcerBlockerType(m_second_selected_extruder_idx + 1); }
@@ -136,13 +121,8 @@ protected:
     size_t                            m_first_selected_extruder_idx  = 0;
     size_t                            m_second_selected_extruder_idx = 1;
     std::vector<std::string>          m_original_extruders_names;
-#if ENABLE_COLOR_CLASSES
     std::vector<ColorRGBA>            m_original_extruders_colors;
     std::vector<ColorRGBA>            m_modified_extruders_colors;
-#else
-    std::vector<std::array<float, 4>> m_original_extruders_colors;
-    std::vector<std::array<float, 4>> m_modified_extruders_colors;
-#endif // ENABLE_COLOR_CLASSES
     std::vector<int>                  m_original_volumes_extruder_idxs;
 
     static const constexpr float      CursorRadiusMin = 0.1f; // cannot be zero
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoMove.cpp b/src/slic3r/GUI/Gizmos/GLGizmoMove.cpp
index c36d448cd..ff6a05847 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoMove.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoMove.cpp
@@ -117,11 +117,7 @@ void GLGizmoMove3D::on_render()
         // draw axes
         for (unsigned int i = 0; i < 3; ++i) {
             if (m_grabbers[i].enabled) {
-#if ENABLE_COLOR_CLASSES
                 glsafe(::glColor4fv(AXES_COLOR[i].data()));
-#else
-                glsafe(::glColor4fv(AXES_COLOR[i].data()));
-#endif // ENABLE_COLOR_CLASSES
                 ::glBegin(GL_LINES);
                 ::glVertex3dv(center.data());
                 ::glVertex3dv(m_grabbers[i].center.data());
@@ -138,11 +134,7 @@ void GLGizmoMove3D::on_render()
     }
     else {
         // draw axis
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(AXES_COLOR[m_hover_id].data()));
-#else
-        glsafe(::glColor4fv(AXES_COLOR[m_hover_id].data()));
-#endif // ENABLE_COLOR_CLASSES
         ::glBegin(GL_LINES);
         ::glVertex3dv(center.data());
         ::glVertex3dv(m_grabbers[m_hover_id].center.data());
@@ -203,19 +195,9 @@ void GLGizmoMove3D::render_grabber_extension(Axis axis, const BoundingBoxf3& box
     float mean_size = (float)((box.size().x() + box.size().y() + box.size().z()) / 3.0);
     double size = m_dragging ? (double)m_grabbers[axis].get_dragging_half_size(mean_size) : (double)m_grabbers[axis].get_half_size(mean_size);
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA color = m_grabbers[axis].color;
     if (!picking && m_hover_id != -1)
         color = complementary(color);
-#else
-    std::array<float, 4> color = m_grabbers[axis].color;
-    if (!picking && m_hover_id != -1) {
-        color[0] = 1.0f - color[0];
-        color[1] = 1.0f - color[1];
-        color[2] = 1.0f - color[2];
-        color[3] = color[3];
-    }
-#endif // ENABLE_COLOR_CLASSES
 
     GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
     if (shader == nullptr)
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
index bfb2d6fef..1f654dcc0 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.cpp
@@ -207,20 +207,12 @@ void GLGizmoPainterBase::render_cursor_sphere(const Transform3d& trafo) const
     if (is_left_handed)
         glFrontFace(GL_CW);
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA render_color = { 0.0f, 0.0f, 0.0f, 0.25f };
-#else
-    std::array<float, 4> render_color = {0.f, 0.f, 0.f, 0.25f};
-#endif // ENABLE_COLOR_CLASSES
     if (m_button_down == Button::Left)
         render_color = this->get_cursor_sphere_left_button_color();
     else if (m_button_down == Button::Right)
         render_color = this->get_cursor_sphere_right_button_color();
-#if ENABLE_COLOR_CLASSES
     glsafe(::glColor4fv(render_color.data()));
-#else
-    glsafe(::glColor4fv(render_color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
     assert(s_sphere != nullptr);
     s_sphere->render();
@@ -717,27 +709,15 @@ TriangleSelector::ClippingPlane GLGizmoPainterBase::get_clipping_plane_in_volume
     return TriangleSelector::ClippingPlane({float(normal_transformed.x()), float(normal_transformed.y()), float(normal_transformed.z()), offset_transformed});
 }
 
-#if ENABLE_COLOR_CLASSES
 ColorRGBA TriangleSelectorGUI::get_seed_fill_color(const ColorRGBA& base_color)
 {
     return saturate(base_color, 0.75f);
 }
-#else
-std::array<float, 4> TriangleSelectorGUI::get_seed_fill_color(const std::array<float, 4> &base_color)
-{
-    return { base_color[0] * 0.75f, base_color[1] * 0.75f, base_color[2] * 0.75f, 1.f };
-}
-#endif // ENABLE_COLOR_CLASSES
 
 void TriangleSelectorGUI::render(ImGuiWrapper* imgui)
 {
-#if ENABLE_COLOR_CLASSES
     static const ColorRGBA enforcers_color = { 0.47f, 0.47f, 1.0f, 1.0f };
     static const ColorRGBA blockers_color  = { 1.0f, 0.44f, 0.44f, 1.0f };
-#else
-    static constexpr std::array<float, 4> enforcers_color{0.47f, 0.47f, 1.f, 1.f};
-    static constexpr std::array<float, 4> blockers_color{1.f, 0.44f, 0.44f, 1.f};
-#endif // ENABLE_COLOR_CLASSES
 
     if (m_update_render_data) {
         update_render_data();
@@ -761,15 +741,9 @@ void TriangleSelectorGUI::render(ImGuiWrapper* imgui)
     for (auto &iva : m_iva_seed_fills)
         if (iva.has_VBOs()) {
             size_t                      color_idx = &iva - &m_iva_seed_fills.front();
-#if ENABLE_COLOR_CLASSES
             const ColorRGBA& color                = TriangleSelectorGUI::get_seed_fill_color(color_idx == 1 ? enforcers_color :
                                                                                              color_idx == 2 ? blockers_color :
                                                                                                               GLVolume::NEUTRAL_COLOR);
-#else
-            const std::array<float, 4> &color     = TriangleSelectorGUI::get_seed_fill_color(color_idx == 1 ? enforcers_color :
-                                                                                             color_idx == 2 ? blockers_color :
-                                                                                                              GLVolume::NEUTRAL_COLOR);
-#endif // ENABLE_COLOR_CLASSES
             shader->set_uniform("uniform_color", color);
             iva.render();
         }
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp
index 2822ec292..53c0f31b1 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoPainterBase.hpp
@@ -86,11 +86,7 @@ public:
 protected:
     bool m_update_render_data = false;
 
-#if ENABLE_COLOR_CLASSES
     static ColorRGBA get_seed_fill_color(const ColorRGBA& base_color);
-#else
-    static std::array<float, 4> get_seed_fill_color(const std::array<float, 4> &base_color);
-#endif // ENABLE_COLOR_CLASSES
 
 private:
     void update_render_data();
@@ -139,13 +135,8 @@ protected:
     virtual void update_model_object() const = 0;
     virtual void update_from_model_object() = 0;
 
-#if ENABLE_COLOR_CLASSES
     virtual ColorRGBA get_cursor_sphere_left_button_color() const  { return { 0.0f, 0.0f, 1.0f, 0.25f }; }
     virtual ColorRGBA get_cursor_sphere_right_button_color() const { return { 1.0f, 0.0f, 0.0f, 0.25f }; }
-#else
-    virtual std::array<float, 4> get_cursor_sphere_left_button_color() const { return {0.f, 0.f, 1.f, 0.25f}; }
-    virtual std::array<float, 4> get_cursor_sphere_right_button_color() const { return {1.f, 0.f, 0.f, 0.25f}; }
-#endif // ENABLE_COLOR_CLASSES
 
     virtual EnforcerBlockerType get_left_button_state_type() const { return EnforcerBlockerType::ENFORCER; }
     virtual EnforcerBlockerType get_right_button_state_type() const { return EnforcerBlockerType::BLOCKER; }
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp b/src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp
index 834b294ee..5046d1922 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoRotate.cpp
@@ -137,11 +137,7 @@ void GLGizmoRotate::on_render()
     transform_to_local(selection);
 
     glsafe(::glLineWidth((m_hover_id != -1) ? 2.0f : 1.5f));
-#if ENABLE_COLOR_CLASSES
     glsafe(::glColor4fv((m_hover_id != -1) ? m_drag_color.data() : m_highlight_color.data()));
-#else
-    glsafe(::glColor4fv((m_hover_id != -1) ? m_drag_color.data() : m_highlight_color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
     render_circle();
 
@@ -151,11 +147,7 @@ void GLGizmoRotate::on_render()
         render_reference_radius();
     }
 
-#if ENABLE_COLOR_CLASSES
     glsafe(::glColor4fv(m_highlight_color.data()));
-#else
-    glsafe(::glColor4fv(m_highlight_color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
     if (m_hover_id != -1)
         render_angle();
@@ -306,11 +298,7 @@ void GLGizmoRotate::render_grabber(const BoundingBoxf3& box) const
     m_grabbers[0].center = Vec3d(::cos(m_angle) * grabber_radius, ::sin(m_angle) * grabber_radius, 0.0);
     m_grabbers[0].angles(2) = m_angle;
 
-#if ENABLE_COLOR_CLASSES
     glsafe(::glColor4fv((m_hover_id != -1) ? m_drag_color.data() : m_highlight_color.data()));
-#else
-    glsafe(::glColor4fv((m_hover_id != -1) ? m_drag_color.data() : m_highlight_color.data()));
-#endif // ENABLE_COLOR_CLASSES
 
     ::glBegin(GL_LINES);
     ::glVertex3f(0.0f, 0.0f, 0.0f);
@@ -326,18 +314,9 @@ void GLGizmoRotate::render_grabber_extension(const BoundingBoxf3& box, bool pick
     float mean_size = (float)((box.size()(0) + box.size()(1) + box.size()(2)) / 3.0);
     double size = m_dragging ? (double)m_grabbers[0].get_dragging_half_size(mean_size) : (double)m_grabbers[0].get_half_size(mean_size);
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA color = m_grabbers[0].color;
     if (!picking && m_hover_id != -1)
         color = complementary(color);
-#else
-    std::array<float, 4> color = m_grabbers[0].color;
-    if (!picking && m_hover_id != -1) {
-        color[0] = 1.0f - color[0];
-        color[1] = 1.0f - color[1];
-        color[2] = 1.0f - color[2];
-    }
-#endif // ENABLE_COLOR_CLASSES
 
     GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
     if (shader == nullptr)
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoScale.cpp b/src/slic3r/GUI/Gizmos/GLGizmoScale.cpp
index 44d0f7dc5..b97507166 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoScale.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoScale.cpp
@@ -209,34 +209,18 @@ void GLGizmoScale3D::on_render()
     if (m_hover_id == -1) {
         // draw connections
         if (m_grabbers[0].enabled && m_grabbers[1].enabled) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(m_grabbers[0].color.data()));
-#else
-            glsafe(::glColor4fv(m_grabbers[0].color.data()));
-#endif // ENABLE_COLOR_CLASSES
             render_grabbers_connection(0, 1);
         }
         if (m_grabbers[2].enabled && m_grabbers[3].enabled) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(m_grabbers[2].color.data()));
-#else
-            glsafe(::glColor4fv(m_grabbers[2].color.data()));
-#endif // ENABLE_COLOR_CLASSES
             render_grabbers_connection(2, 3);
         }
         if (m_grabbers[4].enabled && m_grabbers[5].enabled) {
-#if ENABLE_COLOR_CLASSES
             glsafe(::glColor4fv(m_grabbers[4].color.data()));
-#else
-            glsafe(::glColor4fv(m_grabbers[4].color.data()));
-#endif // ENABLE_COLOR_CLASSES
             render_grabbers_connection(4, 5);
         }
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(m_base_color.data()));
-#else
-        glsafe(::glColor4fv(m_base_color.data()));
-#endif // ENABLE_COLOR_CLASSES
         render_grabbers_connection(6, 7);
         render_grabbers_connection(7, 8);
         render_grabbers_connection(8, 9);
@@ -246,11 +230,7 @@ void GLGizmoScale3D::on_render()
     }
     else if (m_hover_id == 0 || m_hover_id == 1) {
         // draw connection
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(m_grabbers[0].color.data()));
-#else
-        glsafe(::glColor4fv(m_grabbers[0].color.data()));
-#endif // ENABLE_COLOR_CLASSES
         render_grabbers_connection(0, 1);
 
         GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
@@ -265,11 +245,7 @@ void GLGizmoScale3D::on_render()
     }
     else if (m_hover_id == 2 || m_hover_id == 3) {
         // draw connection
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(m_grabbers[2].color.data()));
-#else
-        glsafe(::glColor4fv(m_grabbers[2].color.data()));
-#endif // ENABLE_COLOR_CLASSES
         render_grabbers_connection(2, 3);
 
         GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
@@ -284,11 +260,7 @@ void GLGizmoScale3D::on_render()
     }
     else if (m_hover_id == 4 || m_hover_id == 5) {
         // draw connection
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(m_grabbers[4].color.data()));
-#else
-        glsafe(::glColor4fv(m_grabbers[4].color.data()));
-#endif // ENABLE_COLOR_CLASSES
         render_grabbers_connection(4, 5);
 
         GLShaderProgram* shader = wxGetApp().get_shader("gouraud_light");
@@ -303,11 +275,7 @@ void GLGizmoScale3D::on_render()
     }
     else if (m_hover_id >= 6) {
         // draw connection
-#if ENABLE_COLOR_CLASSES
         glsafe(::glColor4fv(m_drag_color.data()));
-#else
-        glsafe(::glColor4fv(m_drag_color.data()));
-#endif // ENABLE_COLOR_CLASSES
         render_grabbers_connection(6, 7);
         render_grabbers_connection(7, 8);
         render_grabbers_connection(8, 9);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp b/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
index c150c962f..37a107346 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp
@@ -144,11 +144,7 @@ void GLGizmoSlaSupports::render_points(const Selection& selection, bool picking)
     glsafe(::glTranslated(0.0, 0.0, z_shift));
     glsafe(::glMultMatrixd(instance_matrix.data()));
 
-#if ENABLE_COLOR_CLASSES
     ColorRGBA render_color;
-#else
-    std::array<float, 4> render_color;
-#endif // ENABLE_COLOR_CLASSES
     for (size_t i = 0; i < cache_size; ++i) {
         const sla::SupportPoint& support_point = m_editing_mode ? m_editing_cache[i].support_point : m_normal_cache[i];
         const bool& point_selected = m_editing_mode ? m_editing_cache[i].selected : false;
@@ -230,14 +226,7 @@ void GLGizmoSlaSupports::render_points(const Selection& selection, bool picking)
 
     // Now render the drain holes:
     if (has_holes && ! picking) {
-#if ENABLE_COLOR_CLASSES
         render_color = { 0.7f, 0.7f, 0.7f, 0.7f };
-#else
-        render_color[0] = 0.7f;
-        render_color[1] = 0.7f;
-        render_color[2] = 0.7f;
-        render_color[3] = 0.7f;
-#endif // ENABLE_COLOR_CLASSES
         const_cast<GLModel*>(&m_cylinder)->set_color(-1, render_color);
         if (shader)
             shader->set_uniform("emission_factor", 0.5f);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmosCommon.cpp b/src/slic3r/GUI/Gizmos/GLGizmosCommon.cpp
index 405d3bc1e..cc53f267c 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmosCommon.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmosCommon.cpp
@@ -216,13 +216,8 @@ void InstancesHider::render_cut() const
         if (mv->is_model_part())
             glsafe(::glColor3f(0.8f, 0.3f, 0.0f));
         else {
-#if ENABLE_COLOR_CLASSES
             const ColorRGBA color = color_from_model_volume(*mv);
             glsafe(::glColor4fv(color.data()));
-#else
-            const std::array<float, 4>& c = color_from_model_volume(*mv);
-            glsafe(::glColor4f(c[0], c[1], c[2], c[3]));
-#endif // ENABLE_COLOR_CLASSES
         }
         glsafe(::glPushAttrib(GL_DEPTH_TEST));
         glsafe(::glDisable(GL_DEPTH_TEST));
diff --git a/src/slic3r/GUI/ImGuiWrapper.cpp b/src/slic3r/GUI/ImGuiWrapper.cpp
index ea74551d4..fdb2cdce8 100644
--- a/src/slic3r/GUI/ImGuiWrapper.cpp
+++ b/src/slic3r/GUI/ImGuiWrapper.cpp
@@ -25,9 +25,7 @@
 
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Utils.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "3DScene.hpp"
 #include "GUI.hpp"
 #include "I18N.hpp"
@@ -81,7 +79,6 @@ static const std::map<const wchar_t, std::string> font_icons_extra_large = {
 
 };
 
-#if ENABLE_COLOR_CLASSES
 const ImVec4 ImGuiWrapper::COL_GREY_DARK         = { 0.33f, 0.33f, 0.33f, 1.0f };
 const ImVec4 ImGuiWrapper::COL_GREY_LIGHT        = { 0.4f, 0.4f, 0.4f, 1.0f };
 const ImVec4 ImGuiWrapper::COL_ORANGE_DARK       = { 0.67f, 0.36f, 0.19f, 1.0f };
@@ -90,16 +87,6 @@ const ImVec4 ImGuiWrapper::COL_WINDOW_BACKGROUND = { 0.13f, 0.13f, 0.13f, 0.8f }
 const ImVec4 ImGuiWrapper::COL_BUTTON_BACKGROUND = COL_ORANGE_DARK;
 const ImVec4 ImGuiWrapper::COL_BUTTON_HOVERED    = COL_ORANGE_LIGHT;
 const ImVec4 ImGuiWrapper::COL_BUTTON_ACTIVE     = COL_BUTTON_HOVERED;
-#else
-const ImVec4 ImGuiWrapper::COL_GREY_DARK = { 0.333f, 0.333f, 0.333f, 1.0f };
-const ImVec4 ImGuiWrapper::COL_GREY_LIGHT = { 0.4f, 0.4f, 0.4f, 1.0f };
-const ImVec4 ImGuiWrapper::COL_ORANGE_DARK = { 0.757f, 0.404f, 0.216f, 1.0f };
-const ImVec4 ImGuiWrapper::COL_ORANGE_LIGHT = { 1.0f, 0.49f, 0.216f, 1.0f };
-const ImVec4 ImGuiWrapper::COL_WINDOW_BACKGROUND = { 0.133f, 0.133f, 0.133f, 0.8f };
-const ImVec4 ImGuiWrapper::COL_BUTTON_BACKGROUND = COL_ORANGE_DARK;
-const ImVec4 ImGuiWrapper::COL_BUTTON_HOVERED = COL_ORANGE_LIGHT;
-const ImVec4 ImGuiWrapper::COL_BUTTON_ACTIVE = ImGuiWrapper::COL_BUTTON_HOVERED;
-#endif // ENABLE_COLOR_CLASSES
 
 ImGuiWrapper::ImGuiWrapper()
 {
@@ -1024,7 +1011,6 @@ bool ImGuiWrapper::want_any_input() const
     return io.WantCaptureMouse || io.WantCaptureKeyboard || io.WantTextInput;
 }
 
-#if ENABLE_COLOR_CLASSES
 ImU32 ImGuiWrapper::to_ImU32(const ColorRGBA& color)
 {
     return ImGui::GetColorU32({ color.r(), color.g(), color.b(), color.a() });
@@ -1044,7 +1030,6 @@ ColorRGBA ImGuiWrapper::from_ImVec4(const ImVec4& color)
 {
     return { color.x, color.y, color.z, color.w };
 }
-#endif // ENABLE_COLOR_CLASSES
 
 #ifdef __APPLE__
 static const ImWchar ranges_keyboard_shortcuts[] =
diff --git a/src/slic3r/GUI/ImGuiWrapper.hpp b/src/slic3r/GUI/ImGuiWrapper.hpp
index 1da0fcf23..6f8097fc4 100644
--- a/src/slic3r/GUI/ImGuiWrapper.hpp
+++ b/src/slic3r/GUI/ImGuiWrapper.hpp
@@ -9,11 +9,9 @@
 #include <wx/string.h>
 
 #include "libslic3r/Point.hpp"
+#include "libslic3r/Color.hpp"
 
 namespace Slic3r {
-#if ENABLE_COLOR_CLASSES
-class ColorRGBA;
-#endif // ENABLE_COLOR_CLASSES
 namespace Search {
 struct OptionViewParameters;
 } // namespace Search
@@ -129,12 +127,10 @@ public:
     void set_requires_extra_frame() { m_requires_extra_frame = true; }
     void reset_requires_extra_frame() { m_requires_extra_frame = false; }
 
-#if ENABLE_COLOR_CLASSES
     static ImU32 to_ImU32(const ColorRGBA& color);
     static ImVec4 to_ImVec4(const ColorRGBA& color);
     static ColorRGBA from_ImU32(const ImU32& color);
     static ColorRGBA from_ImVec4(const ImVec4& color);
-#endif // ENABLE_COLOR_CLASSES
 
     static const ImVec4 COL_GREY_DARK;
     static const ImVec4 COL_GREY_LIGHT;
diff --git a/src/slic3r/GUI/MsgDialog.cpp b/src/slic3r/GUI/MsgDialog.cpp
index 7b40b127c..a2d65a73c 100644
--- a/src/slic3r/GUI/MsgDialog.cpp
+++ b/src/slic3r/GUI/MsgDialog.cpp
@@ -14,9 +14,7 @@
 
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Utils.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "GUI.hpp"
 #include "format.hpp"
 #include "I18N.hpp"
@@ -140,14 +138,9 @@ static void add_msg_content(wxWindow* parent, wxBoxSizer* content_sizer, wxStrin
     wxFont      font = wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT);
     wxFont      monospace = wxGetApp().code_font();
     wxColour    text_clr = wxGetApp().get_label_clr_default();
-    wxColour    bgr_clr = parent->GetBackgroundColour(); //wxSystemSettings::GetColour(wxSYS_COLOUR_WINDOW);
-#if ENABLE_COLOR_CLASSES
+    wxColour    bgr_clr = parent->GetBackgroundColour();
     auto        text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
     auto        bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
-#else
-    auto        text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-    auto        bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
     const int   font_size = font.GetPointSize();
     int         size[] = { font_size, font_size, font_size, font_size, font_size, font_size, font_size };
     html->SetFonts(font.GetFaceName(), monospace.GetFaceName(), size);
diff --git a/src/slic3r/GUI/PresetComboBoxes.cpp b/src/slic3r/GUI/PresetComboBoxes.cpp
index bbf7a66cc..ed4888a87 100644
--- a/src/slic3r/GUI/PresetComboBoxes.cpp
+++ b/src/slic3r/GUI/PresetComboBoxes.cpp
@@ -24,9 +24,7 @@
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/PrintConfig.hpp"
 #include "libslic3r/PresetBundle.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include "GUI.hpp"
 #include "GUI_App.hpp"
@@ -445,25 +443,13 @@ wxBitmap* PresetComboBox::get_bmp(  std::string bitmap_key, bool wide_icons, con
             bmps.emplace_back(is_compatible ? bitmap_cache().mkclear(norm_icon_width, icon_height) : m_bitmapIncompatible.bmp());
 
         if (m_type == Preset::TYPE_FILAMENT && !filament_rgb.empty()) {
-#if ENABLE_COLOR_CLASSES
             // Paint the color bars.
             ColorRGB color;
             decode_color(filament_rgb, color);
             bmps.emplace_back(bitmap_cache().mksolid(is_single_bar ? wide_icon_width : norm_icon_width, icon_height, color, false, 1, dark_mode));
-#else
-            unsigned char rgb[3];
-            // Paint the color bars.
-            bitmap_cache().parse_color(filament_rgb, rgb);
-            bmps.emplace_back(bitmap_cache().mksolid(is_single_bar ? wide_icon_width : norm_icon_width, icon_height, rgb, false, 1, dark_mode));
-#endif // ENABLE_COLOR_CLASSES
             if (!is_single_bar) {
-#if ENABLE_COLOR_CLASSES
                 decode_color(extruder_rgb, color);
                 bmps.emplace_back(bitmap_cache().mksolid(thin_icon_width, icon_height, color, false, 1, dark_mode));
-#else
-                bitmap_cache().parse_color(extruder_rgb, rgb);
-                bmps.emplace_back(bitmap_cache().mksolid(thin_icon_width, icon_height, rgb, false, 1, dark_mode));
-#endif // ENABLE_COLOR_CLASSES
             }
             // Paint a lock at the system presets.
             bmps.emplace_back(bitmap_cache().mkclear(space_icon_width, icon_height));
@@ -782,15 +768,8 @@ void PlaterPresetComboBox::update()
     const Preset* selected_filament_preset = nullptr;
     std::string extruder_color;
     if (m_type == Preset::TYPE_FILAMENT) {
-#if !ENABLE_COLOR_CLASSES
-        unsigned char rgb[3];
-#endif // !ENABLE_COLOR_CLASSES
         extruder_color = m_preset_bundle->printers.get_edited_preset().config.opt_string("extruder_colour", (unsigned int)m_extruder_idx);
-#if ENABLE_COLOR_CLASSES
         if (!can_decode_color(extruder_color))
-#else
-        if (!bitmap_cache().parse_color(extruder_color, rgb))
-#endif // ENABLE_COLOR_CLASSES
             // Extruder color is not defined.
             extruder_color.clear();
         selected_filament_preset = m_collection->find_preset(m_preset_bundle->filament_presets[m_extruder_idx]);
diff --git a/src/slic3r/GUI/Selection.cpp b/src/slic3r/GUI/Selection.cpp
index c7258b3ae..5aa2cb4d0 100644
--- a/src/slic3r/GUI/Selection.cpp
+++ b/src/slic3r/GUI/Selection.cpp
@@ -22,13 +22,9 @@
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/log/trivial.hpp>
 
-#if ENABLE_COLOR_CLASSES
 static const Slic3r::ColorRGBA UNIFORM_SCALE_COLOR     = Slic3r::ColorRGBA::ORANGE();
 static const Slic3r::ColorRGBA SOLID_PLANE_COLOR       = Slic3r::ColorRGBA::ORANGE();
 static const Slic3r::ColorRGBA TRANSPARENT_PLANE_COLOR = { 0.8f, 0.8f, 0.8f, 0.5f };
-#else
-static const std::array<float, 4> UNIFORM_SCALE_COLOR = { 0.923f, 0.504f, 0.264f, 1.0f };
-#endif // ENABLE_COLOR_CLASSES
 
 namespace Slic3r {
 namespace GUI {
@@ -456,11 +452,7 @@ void Selection::clear()
     for (unsigned int i : m_list) {
         GLVolume& volume = *(*m_volumes)[i];
         volume.selected = false;
-#if ENABLE_COLOR_CLASSES
         bool is_transparent = volume.color.is_transparent();
-#else
-        bool is_transparent = volume.color[3] < 1.0f;
-#endif // ENABLE_COLOR_CLASSES
         if (is_transparent)
             volume.force_transparent = true;
         volume.set_render_color();
@@ -1874,17 +1866,10 @@ void Selection::render_bounding_box(const BoundingBoxf3& box, float* color) cons
     glsafe(::glEnd());
 }
 
-#if ENABLE_COLOR_CLASSES
 static ColorRGBA get_color(Axis axis)
 {
     return AXES_COLOR[axis];
-};
-#else
-static std::array<float, 4> get_color(Axis axis)
-{
-    return { AXES_COLOR[axis][0], AXES_COLOR[axis][1], AXES_COLOR[axis][2], AXES_COLOR[axis][3] };
-};
-#endif // ENABLE_COLOR_CLASSES
+}
 
 void Selection::render_sidebar_position_hints(const std::string& sidebar_field) const
 {
@@ -2014,15 +1999,8 @@ void Selection::render_sidebar_layers_hints(const std::string& sidebar_field) co
     glsafe(::glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
 
     ::glBegin(GL_QUADS);
-#if ENABLE_COLOR_CLASSES
     ::glColor4fv((camera_on_top && type == 1) || (!camera_on_top && type == 2) ?
         SOLID_PLANE_COLOR.data() : TRANSPARENT_PLANE_COLOR.data());
-#else
-    if ((camera_on_top && type == 1) || (!camera_on_top && type == 2))
-        ::glColor4f(1.0f, 0.38f, 0.0f, 1.0f);
-    else
-        ::glColor4f(0.8f, 0.8f, 0.8f, 0.5f);
-#endif // ENABLE_COLOR_CLASSES
     ::glVertex3f(min_x, min_y, z1);
     ::glVertex3f(max_x, min_y, z1);
     ::glVertex3f(max_x, max_y, z1);
@@ -2030,15 +2008,8 @@ void Selection::render_sidebar_layers_hints(const std::string& sidebar_field) co
     glsafe(::glEnd());
 
     ::glBegin(GL_QUADS);
-#if ENABLE_COLOR_CLASSES
     ::glColor4fv((camera_on_top && type == 2) || (!camera_on_top && type == 1) ?
         SOLID_PLANE_COLOR.data() : TRANSPARENT_PLANE_COLOR.data());
-#else
-    if ((camera_on_top && type == 2) || (!camera_on_top && type == 1))
-        ::glColor4f(1.0f, 0.38f, 0.0f, 1.0f);
-    else
-        ::glColor4f(0.8f, 0.8f, 0.8f, 0.5f);
-#endif // ENABLE_COLOR_CLASSES
     ::glVertex3f(min_x, min_y, z2);
     ::glVertex3f(max_x, min_y, z2);
     ::glVertex3f(max_x, max_y, z2);
diff --git a/src/slic3r/GUI/SendSystemInfoDialog.cpp b/src/slic3r/GUI/SendSystemInfoDialog.cpp
index 633f2635f..9a97532a7 100644
--- a/src/slic3r/GUI/SendSystemInfoDialog.cpp
+++ b/src/slic3r/GUI/SendSystemInfoDialog.cpp
@@ -4,9 +4,7 @@
 #include "libslic3r/BlacklistedLibraryCheck.hpp"
 #include "libslic3r/Platform.hpp"
 #include "libslic3r/Utils.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include "slic3r/GUI/format.hpp"
 #include "slic3r/Utils/Http.hpp"
@@ -574,13 +572,8 @@ SendSystemInfoDialog::SendSystemInfoDialog(wxWindow* parent)
     wxColour bgr_clr = wxGetApp().get_window_default_clr();
     SetBackgroundColour(bgr_clr);
     const auto text_clr = wxGetApp().get_label_clr_default();
-#if ENABLE_COLOR_CLASSES
     auto text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
     auto bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
-#else
-    auto text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-    auto bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
 
     auto *topSizer = new wxBoxSizer(wxVERTICAL);
     auto *vsizer = new wxBoxSizer(wxVERTICAL);
diff --git a/src/slic3r/GUI/SysInfoDialog.cpp b/src/slic3r/GUI/SysInfoDialog.cpp
index 3304a573d..06cf2b73d 100644
--- a/src/slic3r/GUI/SysInfoDialog.cpp
+++ b/src/slic3r/GUI/SysInfoDialog.cpp
@@ -15,9 +15,7 @@
 #include "MainFrame.hpp"
 #include "wxExtensions.hpp"
 #include "../libslic3r/BlacklistedLibraryCheck.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "../libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "format.hpp"
 
 #ifdef _WIN32
@@ -117,13 +115,8 @@ SysInfoDialog::SysInfoDialog()
     // main_info_text
     wxFont font = get_default_font(this);
     const auto text_clr = wxGetApp().get_label_clr_default();
-#if ENABLE_COLOR_CLASSES
     auto text_clr_str = encode_color(ColorRGB(text_clr.Red(), text_clr.Green(), text_clr.Blue()));
     auto bgr_clr_str = encode_color(ColorRGB(bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue()));
-#else
-    auto text_clr_str = wxString::Format(wxT("#%02X%02X%02X"), text_clr.Red(), text_clr.Green(), text_clr.Blue());
-    auto bgr_clr_str = wxString::Format(wxT("#%02X%02X%02X"), bgr_clr.Red(), bgr_clr.Green(), bgr_clr.Blue());
-#endif // ENABLE_COLOR_CLASSES
 
     const int fs = font.GetPointSize() - 1;
     int size[] = { static_cast<int>(fs*1.5), static_cast<int>(fs*1.4), static_cast<int>(fs*1.3), fs, fs, fs, fs };
diff --git a/src/slic3r/GUI/UnsavedChangesDialog.cpp b/src/slic3r/GUI/UnsavedChangesDialog.cpp
index 628c395a8..ee057a7aa 100644
--- a/src/slic3r/GUI/UnsavedChangesDialog.cpp
+++ b/src/slic3r/GUI/UnsavedChangesDialog.cpp
@@ -11,9 +11,7 @@
 
 #include "libslic3r/PrintConfig.hpp"
 #include "libslic3r/PresetBundle.hpp"
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 #include "format.hpp"
 #include "GUI_App.hpp"
 #include "Plater.hpp"
@@ -61,12 +59,7 @@ static std::string get_icon_name(Preset::Type type, PrinterTechnology pt) {
 static std::string def_text_color()
 {
     wxColour def_colour = wxGetApp().get_label_clr_default();
-#if ENABLE_COLOR_CLASSES
     return encode_color(ColorRGB(def_colour.Red(), def_colour.Green(), def_colour.Blue()));
-#else
-    auto clr_str = wxString::Format(wxT("#%02X%02X%02X"), def_colour.Red(), def_colour.Green(), def_colour.Blue());
-    return clr_str.ToStdString();
-#endif // ENABLE_COLOR_CLASSES
 }
 static std::string grey     = "#808080";
 static std::string orange   = "#ed6b21";
@@ -131,13 +124,8 @@ wxBitmap ModelNode::get_bitmap(const wxString& color)
     const int icon_height   = lround(1.6 * em);
 
     BitmapCache bmp_cache;
-#if ENABLE_COLOR_CLASSES
     ColorRGB rgb;
     decode_color(into_u8(color), rgb);
-#else
-    unsigned char rgb[3];
-    BitmapCache::parse_color(into_u8(color), rgb);
-#endif // ENABLE_COLOR_CLASSES
     // there is no need to scale created solid bitmap
 #ifndef __linux__
     return bmp_cache.mksolid(icon_width, icon_height, rgb, true);
diff --git a/src/slic3r/GUI/WipeTowerDialog.cpp b/src/slic3r/GUI/WipeTowerDialog.cpp
index e984738db..4d117ff8d 100644
--- a/src/slic3r/GUI/WipeTowerDialog.cpp
+++ b/src/slic3r/GUI/WipeTowerDialog.cpp
@@ -7,9 +7,7 @@
 #include "GUI_App.hpp"
 #include "MsgDialog.hpp"
 
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #include <wx/sizer.h>
 
@@ -230,15 +228,9 @@ WipingPanel::WipingPanel(wxWindow* parent, const std::vector<float>& matrix, con
     m_number_of_extruders = (int)(sqrt(matrix.size())+0.001);
 
     for (const std::string& color : extruder_colours) {
-#if ENABLE_COLOR_CLASSES
         Slic3r::ColorRGB rgb;
         Slic3r::decode_color(color, rgb);
         m_colours.push_back(wxColor(rgb.r_uchar(), rgb.g_uchar(), rgb.b_uchar()));
-#else
-        unsigned char rgb[3];
-        Slic3r::GUI::BitmapCache::parse_color(color, rgb);
-        m_colours.push_back(wxColor(rgb[0], rgb[1], rgb[2]));
-#endif // ENABLE_COLOR_CLASSES
     }
 
 	// Create two switched panels with their own sizers
diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index 23774e8d8..ebd854cc3 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -18,9 +18,7 @@
 #include "BitmapComboBox.hpp"
 #include "OG_CustomCtrl.hpp"
 
-#if ENABLE_COLOR_CLASSES
 #include "libslic3r/Color.hpp"
-#endif // ENABLE_COLOR_CLASSES
 
 #ifndef __linux__
 // msw_menuitem_bitmaps is used for MSW and OSX
@@ -476,10 +474,6 @@ std::vector<wxBitmap*> get_extruder_color_icons(bool thin_icon/* = false*/)
     if (colors.empty())
         return bmps;
 
-#if !ENABLE_COLOR_CLASSES
-    unsigned char rgb[3];
-#endif // !ENABLE_COLOR_CLASSES
-
     /* It's supposed that standard size of an icon is 36px*16px for 100% scaled display.
      * So set sizes for solid_colored icons used for filament preset
      * and scale them in respect to em_unit value
@@ -496,18 +490,11 @@ std::vector<wxBitmap*> get_extruder_color_icons(bool thin_icon/* = false*/)
 
         wxBitmap* bitmap = bmp_cache.find(bitmap_key);
         if (bitmap == nullptr) {
-#if ENABLE_COLOR_CLASSES
             // Paint the color icon.
             Slic3r::ColorRGB rgb;
             Slic3r::decode_color(color, rgb);
             // there is no neede to scale created solid bitmap
             bitmap = bmp_cache.insert(bitmap_key, bmp_cache.mksolid(icon_width, icon_height, rgb, true, 1, dark_mode));
-#else
-            // Paint the color icon.
-            Slic3r::GUI::BitmapCache::parse_color(color, rgb);
-            // there is no neede to scale created solid bitmap
-            bitmap = bmp_cache.insert(bitmap_key, bmp_cache.mksolid(icon_width, icon_height, rgb, true, 1, dark_mode));
-#endif // ENABLE_COLOR_CLASSES
         }
         bmps.emplace_back(bitmap);
     }