diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 3e1ee9f9f..c01a1f6aa 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2630,28 +2630,19 @@ void PrintConfigDef::init_sla_params()
     def->min = 0;
     def->default_value = new ConfigOptionFloat(5.0);
 
-    def = this->add("support_density_at_horizontal", coInt);
-    def->label = L("Density on horizontal surfaces");
+    def = this->add("support_points_density_relative", coInt);
+    def->label = L("Support points density");
     def->category = L("Supports");
-    def->tooltip = L("How many support points (approximately) should be placed on horizontal surface.");
-    def->sidetext = L("points per square dm");
+    def->tooltip = L("This is a relative measure of support points density.");
+    def->sidetext = L("%");
     def->cli = "";
     def->min = 0;
-    def->default_value = new ConfigOptionInt(500);
+    def->default_value = new ConfigOptionInt(100);
 
-    def = this->add("support_density_at_45", coInt);
-    def->label = L("Density on surfaces at 45 degrees");
+    def = this->add("support_points_minimal_distance", coFloat);
+    def->label = L("Minimal distance of the support points");
     def->category = L("Supports");
-    def->tooltip = L("How many support points (approximately) should be placed on surface sloping at 45 degrees.");
-    def->sidetext = L("points per square dm");
-    def->cli = "";
-    def->min = 0;
-    def->default_value = new ConfigOptionInt(250);
-
-    def = this->add("support_minimal_z", coFloat);
-    def->label = L("Minimal support point height");
-    def->category = L("Supports");
-    def->tooltip = L("No support points will be placed lower than this value from the bottom.");
+    def->tooltip = L("No support points will be placed closer than this threshold.");
     def->sidetext = L("mm");
     def->cli = "";
     def->min = 0;
diff --git a/src/libslic3r/PrintConfig.hpp b/src/libslic3r/PrintConfig.hpp
index 20c089d1c..c6c917515 100644
--- a/src/libslic3r/PrintConfig.hpp
+++ b/src/libslic3r/PrintConfig.hpp
@@ -1002,9 +1002,8 @@ public:
     ConfigOptionFloat support_object_elevation /*= 5.0*/;
 
     /////// Following options influence automatic support points placement:
-    ConfigOptionInt support_density_at_horizontal;
-    ConfigOptionInt support_density_at_45;
-    ConfigOptionFloat support_minimal_z;
+    ConfigOptionInt support_points_density_relative;
+    ConfigOptionFloat support_points_minimal_distance;
 
     // Now for the base pool (pad) /////////////////////////////////////////////
 
@@ -1040,9 +1039,8 @@ protected:
         OPT_PTR(support_base_height);
         OPT_PTR(support_critical_angle);
         OPT_PTR(support_max_bridge_length);
-        OPT_PTR(support_density_at_horizontal);
-        OPT_PTR(support_density_at_45);
-        OPT_PTR(support_minimal_z);
+        OPT_PTR(support_points_density_relative);
+        OPT_PTR(support_points_minimal_distance);
         OPT_PTR(support_object_elevation);
         OPT_PTR(pad_enable);
         OPT_PTR(pad_wall_thickness);
diff --git a/src/libslic3r/SLA/SLAAutoSupports.cpp b/src/libslic3r/SLA/SLAAutoSupports.cpp
index e8cb940b7..1f6dcc2b7 100644
--- a/src/libslic3r/SLA/SLAAutoSupports.cpp
+++ b/src/libslic3r/SLA/SLAAutoSupports.cpp
@@ -233,7 +233,7 @@ void SLAAutoSupports::process(const std::vector<ExPolygons>& slices, const std::
 //            s.supports_force_inherited /= std::max(1.f, (layer_height / 0.3f) * e_area / s.area);
             s.supports_force_inherited /= std::max(1.f, 0.17f * (s.overhangs_area) / s.area);
 
-            float force_deficit = s.support_force_deficit(m_config.tear_pressure);
+            float force_deficit = s.support_force_deficit(m_config.tear_pressure());
             if (s.islands_below.empty()) { // completely new island - needs support no doubt
                 uniformly_cover({ *s.polygon }, s, point_grid, true);
             } else if (! s.dangling_areas.empty()) {
@@ -439,16 +439,16 @@ void SLAAutoSupports::uniformly_cover(const ExPolygons& islands, Structure& stru
 {
     //int num_of_points = std::max(1, (int)((island.area()*pow(SCALING_FACTOR, 2) * m_config.tear_pressure)/m_config.support_force));
 
-    const float support_force_deficit = structure.support_force_deficit(m_config.tear_pressure);
+    const float support_force_deficit = structure.support_force_deficit(m_config.tear_pressure());
     if (support_force_deficit < 0)
         return;
 
     // Number of newly added points.
-    const size_t poisson_samples_target = size_t(ceil(support_force_deficit / m_config.support_force));
+    const size_t poisson_samples_target = size_t(ceil(support_force_deficit / m_config.support_force()));
 
-    const float density_horizontal = m_config.tear_pressure / m_config.support_force;
+    const float density_horizontal = m_config.tear_pressure() / m_config.support_force();
     //FIXME why?
-    float poisson_radius		= 1.f / (5.f * density_horizontal);
+    float poisson_radius		= std::max(m_config.minimal_distance, 1.f / (5.f * density_horizontal));
 //    const float poisson_radius     = 1.f / (15.f * density_horizontal);
     const float samples_per_mm2 = 30.f / (float(M_PI) * poisson_radius * poisson_radius);
     // Minimum distance between samples, in 3D space.
@@ -465,13 +465,13 @@ void SLAAutoSupports::uniformly_cover(const ExPolygons& islands, Structure& stru
             [&structure, &grid3d, min_spacing](const Vec2f &pos) {
                 return grid3d.collides_with(pos, &structure, min_spacing);
             });
-        if (poisson_samples.size() >= poisson_samples_target)
+        if (poisson_samples.size() >= poisson_samples_target || m_config.minimal_distance > poisson_radius-EPSILON)
             break;
         float coeff = 0.5f;
         if (poisson_samples.size() * 2 > poisson_samples_target)
             coeff = float(poisson_samples.size()) / float(poisson_samples_target);
-        poisson_radius *= coeff;
-        min_spacing *= coeff;
+        poisson_radius = std::max(m_config.minimal_distance, poisson_radius * coeff);
+        min_spacing    = std::max(m_config.minimal_distance, min_spacing * coeff);
     }
 
 #ifdef SLA_AUTOSUPPORTS_DEBUG
@@ -494,7 +494,7 @@ void SLAAutoSupports::uniformly_cover(const ExPolygons& islands, Structure& stru
     }
     for (const Vec2f &pt : poisson_samples) {
         m_output.emplace_back(float(pt(0)), float(pt(1)), structure.height, 0.2f, is_new_island);
-        structure.supports_force_this_layer += m_config.support_force;
+        structure.supports_force_this_layer += m_config.support_force();
         grid3d.insert(pt, &structure);
     }
 }
diff --git a/src/libslic3r/SLA/SLAAutoSupports.hpp b/src/libslic3r/SLA/SLAAutoSupports.hpp
index f43cc9faa..b552d1c0b 100644
--- a/src/libslic3r/SLA/SLAAutoSupports.hpp
+++ b/src/libslic3r/SLA/SLAAutoSupports.hpp
@@ -14,13 +14,11 @@ namespace Slic3r {
 class SLAAutoSupports {
 public:
     struct Config {
-            float density_at_horizontal;
-            float density_at_45;
-            float minimal_z;
+            float density_relative;
+            float minimal_distance;
             ///////////////
-//            float support_force = 30.f; // a force one point can support       (arbitrary force unit)
-            float support_force = 10.f; // a force one point can support       (arbitrary force unit)
-			float tear_pressure = 1.f; // pressure that the display exerts    (the force unit per mm2)
+            inline float support_force() const { return 10.f / density_relative; } // a force one point can support       (arbitrary force unit)
+            inline float tear_pressure() const { return 1.f; }  // pressure that the display exerts    (the force unit per mm2)
         };
 
     SLAAutoSupports(const TriangleMesh& mesh, const sla::EigenMesh3D& emesh, const std::vector<ExPolygons>& slices,
diff --git a/src/libslic3r/SLA/SLACommon.hpp b/src/libslic3r/SLA/SLACommon.hpp
index ab535fb9e..f7c0acf33 100644
--- a/src/libslic3r/SLA/SLACommon.hpp
+++ b/src/libslic3r/SLA/SLACommon.hpp
@@ -33,6 +33,7 @@ struct SupportPoint {
     pos(data(0), data(1), data(2)), head_front_radius(data(3)), is_new_island(data(4) != 0.f) {}
 
     bool operator==(const SupportPoint& sp) const { return (pos==sp.pos) && head_front_radius==sp.head_front_radius && is_new_island==sp.is_new_island; }
+    bool operator!=(const SupportPoint& sp) const { return !(sp == (*this)); }
 };
 
 
diff --git a/src/libslic3r/SLAPrint.cpp b/src/libslic3r/SLAPrint.cpp
index 4865150c2..d0c6bfdef 100644
--- a/src/libslic3r/SLAPrint.cpp
+++ b/src/libslic3r/SLAPrint.cpp
@@ -532,9 +532,8 @@ void SLAPrint::process()
             this->throw_if_canceled();
             SLAAutoSupports::Config config;
             const SLAPrintObjectConfig& cfg = po.config();
-            config.minimal_z = float(cfg.support_minimal_z);
-            config.density_at_45 = cfg.support_density_at_45 / 10000.f;
-            config.density_at_horizontal = cfg.support_density_at_horizontal / 10000.f;
+            config.density_relative = (float)cfg.support_points_density_relative / 100.f; // the config value is in percents
+            config.minimal_distance = cfg.support_points_minimal_distance;
 
             // Construction of this object does the calculation.
             this->throw_if_canceled();
@@ -1064,7 +1063,10 @@ bool SLAPrintObject::invalidate_state_by_config_options(const std::vector<t_conf
     for (const t_config_option_key &opt_key : opt_keys) {
 		if (opt_key == "layer_height") {
 			steps.emplace_back(slaposObjectSlice);
-        } else if (opt_key == "supports_enable") {
+        } else if (
+               opt_key == "supports_enable"
+            || opt_key == "support_points_density_relative"
+            || opt_key == "support_points_minimal_distance") {
             steps.emplace_back(slaposSupportPoints);
 		} else if (
                opt_key == "support_head_front_diameter"
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index b4d050d27..98d7b43a1 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -3158,6 +3158,7 @@ void GLCanvas3D::Gizmos::update_on_off_state(const GLCanvas3D& canvas, const Vec
     float cnv_h = (float)canvas.get_canvas_size().get_height();
     float height = _get_total_overlay_height();
     float top_y = 0.5f * (cnv_h - height) + m_overlay_border;
+
     for (GizmosMap::iterator it = m_gizmos.begin(); it != m_gizmos.end(); ++it)
     {
         if ((it->second == nullptr) || !it->second->is_selectable())
@@ -5448,10 +5449,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
 
             m_dirty = true;
         }
-        /*else if ((selected_object_idx != -1) && m_gizmos.grabber_contains_mouse() && evt.RightDown()) {
-            if (m_gizmos.get_current_type() == Gizmos::SlaSupports)
-                m_gizmos.delete_current_grabber();
-        }*/
+        else if ((selected_object_idx != -1) && evt.RightDown() && m_gizmos.get_current_type() == Gizmos::SlaSupports && m_gizmos.mouse_event(SLAGizmoEventType::RightDown))
+        {
+            // event was taken care of by the SlaSupports gizmo
+        }
         else if (view_toolbar_contains_mouse != -1)
         {
             if (m_view_toolbar != nullptr)
@@ -5691,9 +5692,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             post_event(SimpleEvent(EVT_GLCANVAS_MOUSE_DRAGGING_FINISHED));
         }
         else if (evt.LeftUp() && !m_mouse.dragging && (m_hover_volume_id == -1) && !gizmos_overlay_contains_mouse && !m_gizmos.is_dragging()
-              && !is_layers_editing_enabled() && m_gizmos.get_current_type() != Gizmos::SlaSupports)
+              && !is_layers_editing_enabled() && (m_gizmos.get_current_type() != Gizmos::SlaSupports || !m_gizmos.mouse_event(SLAGizmoEventType::LeftUp, Vec2d(pos(0), pos(1)), evt.ShiftDown())))
         {
             // SLA gizmo cannot be deselected by clicking in canvas area to avoid inadvertent unselection and losing manual changes
+            // that's why the mouse_event function was called so that the gizmo can refuse the deselection in manual editing mode
 
             // deselect and propagate event through callback
             if (!evt.ShiftDown() && m_picking_enabled && !m_toolbar_action_running && !m_mouse.ignore_up_event)
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index ff69f1ef8..6b3839b4f 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -136,6 +136,7 @@ wxDECLARE_EVENT(EVT_GLCANVAS_MOUSE_DRAGGING_FINISHED, SimpleEvent);
 enum class SLAGizmoEventType {
     LeftDown = 1,
     LeftUp,
+    RightDown,
     Dragging,
     Delete,
     SelectAll,
diff --git a/src/slic3r/GUI/GLGizmo.cpp b/src/slic3r/GUI/GLGizmo.cpp
index 259fc4ca7..e7b31e309 100644
--- a/src/slic3r/GUI/GLGizmo.cpp
+++ b/src/slic3r/GUI/GLGizmo.cpp
@@ -1784,23 +1784,15 @@ void GLGizmoSlaSupports::set_sla_support_data(ModelObject* model_object, const G
 
     m_active_instance = selection.get_instance_idx();
 
-    if ((model_object != nullptr) && selection.is_from_single_instance())
+    if (model_object && selection.is_from_single_instance())
     {
         if (is_mesh_update_necessary())
             update_mesh();
 
         // If there are no points, let's ask the backend if it calculated some.
-        if (m_editing_mode_cache.empty() && m_parent.sla_print()->is_step_done(slaposSupportPoints)) {
-            for (const SLAPrintObject* po : m_parent.sla_print()->objects()) {
-                if (po->model_object()->id() == model_object->id()) {
-                    const std::vector<sla::SupportPoint>& points = po->get_support_points();
-                    auto mat = po->trafo().inverse().cast<float>();
-                    for (unsigned int i=0; i<points.size();++i)
-						m_editing_mode_cache.emplace_back(sla::SupportPoint(mat * points[i].pos, points[i].head_front_radius, points[i].is_new_island), false);
-                    break;
-                }
-            }
-        }
+        if (m_editing_mode_cache.empty() && m_parent.sla_print()->is_step_done(slaposSupportPoints))
+            get_data_from_backend();
+
         if (m_model_object != m_old_model_object)
             m_editing_mode = false;
         if (m_state == On) {
@@ -1919,7 +1911,7 @@ void GLGizmoSlaSupports::render_points(const GLCanvas3D::Selection& selection, b
             }
         }
         ::glColor3fv(render_color);
-        float render_color_emissive[4] = { 0.5 * render_color[0], 0.5 * render_color[1], 0.5 * render_color[2], 1.f};
+        float render_color_emissive[4] = { 0.5f * render_color[0], 0.5f * render_color[1], 0.5f * render_color[2], 1.f};
         ::glMaterialfv(GL_FRONT, GL_EMISSION, render_color_emissive);
 
         // Now render the sphere. Inverse matrix of the instance scaling is applied so that the
@@ -1981,9 +1973,7 @@ void GLGizmoSlaSupports::update_mesh()
     m_AABB.init(m_V, m_F);
 
     // we'll now reload support points (selection might have changed):
-    m_editing_mode_cache.clear();
-    for (const sla::SupportPoint& point : m_model_object->sla_support_points)
-        m_editing_mode_cache.push_back(std::make_pair(point, false));
+    editing_mode_reload_cache();
 }
 
 Vec3f GLGizmoSlaSupports::unproject_on_mesh(const Vec2d& mouse_pos)
@@ -2045,7 +2035,7 @@ bool GLGizmoSlaSupports::mouse_event(SLAGizmoEventType action, const Vec2d& mous
             m_canvas_height = m_parent.get_canvas_size().get_height();
         }
         else
-            m_editing_mode_cache[m_hover_id].second = true;
+            select_point(m_hover_id);
 
         return true;
     }
@@ -2075,16 +2065,16 @@ bool GLGizmoSlaSupports::mouse_event(SLAGizmoEventType action, const Vec2d& mous
             return false;
 
         // Regardless of whether the user clicked the object or not, we will unselect all points:
-        for (unsigned int i=0; i<m_editing_mode_cache.size(); ++i)
-            m_editing_mode_cache[i].second = false;
+        select_point(NoPoints);
 
         Vec3f new_pos;
         try {
             new_pos = unproject_on_mesh(mouse_position); // this can throw - we don't want to create a new point in that case
             m_editing_mode_cache.emplace_back(std::make_pair(sla::SupportPoint(new_pos, m_new_point_head_diameter/2.f, false), true));
+            m_unsaved_changes = true;
         }
-        catch (...) {       // not clicked on object
-            return false;   // GLCanvas3D might want to deselect the gizmo
+        catch (...) {      // not clicked on object
+            return true;   // prevents deselection of the gizmo by GLCanvas3D
         }
         return true;
     }
@@ -2148,10 +2138,19 @@ bool GLGizmoSlaSupports::mouse_event(SLAGizmoEventType action, const Vec2d& mous
         return true;
     }
 
-    if (action == SLAGizmoEventType::SelectAll) {
-        for (auto& point_and_selection : m_editing_mode_cache)
-            point_and_selection.second = true;
+    if (action == SLAGizmoEventType::RightDown) {
+        if (m_hover_id != -1) {
+            select_point(NoPoints);
+            select_point(m_hover_id);
+            delete_selected_points();
             return true;
+        }
+        return false;
+    }
+
+    if (action == SLAGizmoEventType::SelectAll) {
+        select_point(AllPoints);
+        return true;
     }
 
     return false;
@@ -2163,8 +2162,10 @@ void GLGizmoSlaSupports::delete_selected_points()
         return;
 
     for (unsigned int idx=0; idx<m_editing_mode_cache.size(); ++idx) {
-        if (m_editing_mode_cache[idx].second && (!m_editing_mode_cache[idx].first.is_new_island || !m_lock_unique_islands))
+        if (m_editing_mode_cache[idx].second && (!m_editing_mode_cache[idx].first.is_new_island || !m_lock_unique_islands)) {
             m_editing_mode_cache.erase(m_editing_mode_cache.begin() + (idx--));
+            m_unsaved_changes = true;
+        }
             // This should trigger the support generation
             // wxGetApp().plater()->reslice();
     }
@@ -2182,6 +2183,7 @@ void GLGizmoSlaSupports::on_update(const UpdateData& data, const GLCanvas3D::Sel
         catch (...) { return; }
         m_editing_mode_cache[m_hover_id].first.pos = new_pos;
         m_editing_mode_cache[m_hover_id].first.is_new_island = false;
+        m_unsaved_changes = true;
         // Do not update immediately, wait until the mouse is released.
         // m_parent.post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));
     }
@@ -2237,6 +2239,7 @@ RENDER_AGAIN:
 
     if (m_editing_mode) {
         m_imgui->text(_(L("Left mouse click - add point")));
+        m_imgui->text(_(L("Right mouse click - remove point")));
         m_imgui->text(_(L("Shift + Left (+ drag) - select point(s)")));
         m_imgui->text(" ");  // vertical gap
 
@@ -2250,12 +2253,16 @@ RENDER_AGAIN:
         force_refresh |= (old_combo_state != m_combo_box_open);
 
         float current_number = atof(str);
+        if (old_combo_state && !m_combo_box_open) // closing the combo must always change the sizes (even if the selection did not change)
+            for (auto& point_and_selection : m_editing_mode_cache)
+                if (point_and_selection.second) {
+                    point_and_selection.first.head_front_radius = current_number / 2.f;
+                    m_unsaved_changes = true;
+                }
+
         if (std::abs(current_number - m_new_point_head_diameter) > 0.001) {
             force_refresh = true;
             m_new_point_head_diameter = current_number;
-            for (auto& point_and_selection : m_editing_mode_cache)
-                if (point_and_selection.second)
-                    point_and_selection.first.head_front_radius = current_number / 2.f;
         }
 
         bool changed = m_lock_unique_islands;
@@ -2268,30 +2275,25 @@ RENDER_AGAIN:
 
         bool apply_changes = m_imgui->button(_(L("Apply changes")));
         if (apply_changes) {
-            m_model_object->sla_support_points.clear();
-            for (const std::pair<sla::SupportPoint, bool>& point_and_selection : m_editing_mode_cache)
-                m_model_object->sla_support_points.push_back(point_and_selection.first);
-            m_editing_mode = false;
+            editing_mode_apply_changes();
             force_refresh = true;
             m_parent.post_event(SimpleEvent(EVT_GLCANVAS_SCHEDULE_BACKGROUND_PROCESS));
         }
         ImGui::SameLine();
         bool discard_changes = m_imgui->button(_(L("Discard changes")));
         if (discard_changes) {
-            m_editing_mode_cache.clear();
-            for (const sla::SupportPoint& point : m_model_object->sla_support_points)
-                m_editing_mode_cache.push_back(std::make_pair(point, false));
-            m_editing_mode = false;
+            editing_mode_discard_changes();
             force_refresh = true;
         }
     }
     else {
-        //m_imgui->text("Some settings could");
-        //m_imgui->text("be exposed here...");
-        m_imgui->text("");
-        m_imgui->text("");
-
-        m_imgui->text("");
+       /* ImGui::PushItemWidth(50.0f);
+        m_imgui->text(_(L("Minimal points distance: ")));
+        ImGui::SameLine();
+        bool value_changed = ImGui::InputDouble("mm", &m_minimal_point_distance, 0.0f, 0.0f, "%.2f");
+        m_imgui->text(_(L("Support points density: ")));
+        ImGui::SameLine();
+        value_changed |= ImGui::InputDouble("%", &m_density, 0.0f, 0.0f, "%.f");*/
 
         bool generate = m_imgui->button(_(L("Auto-generate points")));
 
@@ -2302,21 +2304,21 @@ RENDER_AGAIN:
             force_refresh = true;
 #else
             wxMessageDialog dlg(GUI::wxGetApp().plater(), _(L(
-                        "Autogeneration will erase all currently assigned points.\n\n"
+                        "Autogeneration will erase all manually edited points.\n\n"
                         "Are you sure you want to do it?\n"
                         )), _(L("Warning")), wxICON_WARNING | wxYES | wxNO);
-                    if (dlg.ShowModal() == wxID_YES) {
-                        m_model_object->sla_support_points.clear();
-                        m_editing_mode_cache.clear();
-                        wxGetApp().plater()->reslice();
-                    }
+            if (m_model_object->sla_support_points.empty() || dlg.ShowModal() == wxID_YES) {
+                m_model_object->sla_support_points.clear();
+                m_editing_mode_cache.clear();
+                wxGetApp().plater()->reslice();
+            }
 #endif
         }
 #if SLAGIZMO_IMGUI_MODAL
         if (m_show_modal) {
             if (ImGui::BeginPopupModal(_(L("Warning")), &m_show_modal/*, ImGuiWindowFlags_NoDecoration*/))
             {
-                m_imgui->text(_(L("Autogeneration will erase all currently assigned points.")));
+                m_imgui->text(_(L("Autogeneration will erase all manually edited points.")));
                 m_imgui->text("");
                 m_imgui->text(_(L("Are you sure you want to do it?")));
 
@@ -2341,12 +2343,11 @@ RENDER_AGAIN:
                 force_refresh = true;
         }
 #endif
-        ImGui::SameLine();
-        bool editing_clicked = m_imgui->button("Editing");
+        m_imgui->text("");
+        m_imgui->text("");
+        bool editing_clicked = m_imgui->button(_(L("Manual editing")));
         if (editing_clicked) {
-            m_editing_mode_cache.clear();
-            for (const sla::SupportPoint& point : m_model_object->sla_support_points)
-                m_editing_mode_cache.push_back(std::make_pair(point, false));
+            editing_mode_reload_cache();
             m_editing_mode = true;
         }
     }
@@ -2376,8 +2377,17 @@ RENDER_AGAIN:
 
 bool GLGizmoSlaSupports::on_is_activable(const GLCanvas3D::Selection& selection) const
 {
-    return (wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() == ptSLA)
-        && selection.is_from_single_instance();
+    if (wxGetApp().preset_bundle->printers.get_edited_preset().printer_technology() != ptSLA
+        || !selection.is_from_single_instance())
+            return false;
+
+    // Check that none of the selected volumes is outside.
+    const GLCanvas3D::Selection::IndicesList& list = selection.get_volume_idxs();
+    for (const auto& idx : list)
+        if (selection.get_volume(idx)->is_outside)
+            return false;
+
+    return true;
 }
 
 bool GLGizmoSlaSupports::on_is_selectable() const
@@ -2401,29 +2411,94 @@ void GLGizmoSlaSupports::on_set_state()
             m_parent.toggle_model_objects_visibility(true, m_model_object, m_active_instance);
     }
     if (m_state == Off) {
-        m_parent.toggle_model_objects_visibility(true);
-        m_editing_mode_cache.clear();
-        if (m_model_object)
-            for (const sla::SupportPoint& point : m_model_object->sla_support_points)
-                m_editing_mode_cache.push_back(std::make_pair(point, false));
-        m_editing_mode = false;
+        if (m_old_state != Off && m_model_object) { // the gizmo was just turned Off
+
+            if (m_unsaved_changes) {
+                wxMessageDialog dlg(GUI::wxGetApp().plater(), _(L("Do you want to save your manually edited support points ?\n")),
+                                    _(L("Save changes?")), wxICON_QUESTION | wxYES | wxNO);
+                if (dlg.ShowModal() == wxID_YES)
+                    editing_mode_apply_changes();
+                else
+                    editing_mode_discard_changes();
+            }
+
+            m_parent.toggle_model_objects_visibility(true);
+            m_editing_mode = false; // so it is not active next time the gizmo opens
 
 #if SLAGIZMO_IMGUI_MODAL
-        if (m_show_modal) {
-            m_show_modal = false;
-            on_render_input_window(0,0,m_parent.get_selection()); // this is necessary to allow ImGui to terminate the modal dialog correctly
-        }
+            if (m_show_modal) {
+                m_show_modal = false;
+                on_render_input_window(0,0,m_parent.get_selection()); // this is necessary to allow ImGui to terminate the modal dialog correctly
+            }
 #endif
+        }
     }
+    m_old_state = m_state;
 }
 
 void GLGizmoSlaSupports::on_start_dragging(const GLCanvas3D::Selection& selection)
 {
-    if (m_hover_id != -1)
-        for (unsigned int i=0;i<m_editing_mode_cache.size();++i)
-            m_editing_mode_cache[i].second = ((int)i == m_hover_id);
+    if (m_hover_id != -1) {
+        select_point(NoPoints);
+        select_point(m_hover_id);
+    }
 }
 
+void GLGizmoSlaSupports::select_point(int i)
+{
+    if (i == AllPoints || i == NoPoints) {
+        for (auto& point_and_selection : m_editing_mode_cache)
+            point_and_selection.second = ( i == AllPoints ? true : false);
+    }
+    else
+        m_editing_mode_cache[i].second = true;
+}
+
+void GLGizmoSlaSupports::editing_mode_discard_changes()
+{
+    m_editing_mode_cache.clear();
+    for (const sla::SupportPoint& point : m_model_object->sla_support_points)
+        m_editing_mode_cache.push_back(std::make_pair(point, false));
+    m_editing_mode = false;
+    m_unsaved_changes = false;
+}
+
+void GLGizmoSlaSupports::editing_mode_apply_changes()
+{
+    // If there are no changes, don't touch the front-end. The data in the cache could have been
+    // taken from the backend and copying them to ModelObject would needlessly invalidate them.
+    if (m_unsaved_changes) {
+        m_model_object->sla_support_points.clear();
+        for (const std::pair<sla::SupportPoint, bool>& point_and_selection : m_editing_mode_cache)
+            m_model_object->sla_support_points.push_back(point_and_selection.first);
+    }
+    m_editing_mode = false;
+    m_unsaved_changes = false;
+}
+
+void GLGizmoSlaSupports::editing_mode_reload_cache()
+{
+    m_editing_mode_cache.clear();
+    for (const sla::SupportPoint& point : m_model_object->sla_support_points)
+        m_editing_mode_cache.push_back(std::make_pair(point, false));
+    m_unsaved_changes = false;
+}
+
+void GLGizmoSlaSupports::get_data_from_backend()
+{
+    for (const SLAPrintObject* po : m_parent.sla_print()->objects()) {
+        if (po->model_object()->id() == m_model_object->id()) {
+            const std::vector<sla::SupportPoint>& points = po->get_support_points();
+            auto mat = po->trafo().inverse().cast<float>();
+            for (unsigned int i=0; i<points.size();++i)
+                m_editing_mode_cache.emplace_back(sla::SupportPoint(mat * points[i].pos, points[i].head_front_radius, points[i].is_new_island), false);
+            break;
+        }
+    }
+    m_unsaved_changes = false;
+
+    // We don't copy the data into ModelObject, as this would stop the background processing.
+}
 
 
 // GLGizmoCut
diff --git a/src/slic3r/GUI/GLGizmo.hpp b/src/slic3r/GUI/GLGizmo.hpp
index 1605700b1..97e3d0c6f 100644
--- a/src/slic3r/GUI/GLGizmo.hpp
+++ b/src/slic3r/GUI/GLGizmo.hpp
@@ -492,6 +492,8 @@ private:
     bool m_lock_unique_islands = false;
     bool m_editing_mode = false;
     float m_new_point_head_diameter = 0.4f;
+    double m_minimal_point_distance = 20.;
+    double m_density = 100.;
     std::vector<std::pair<sla::SupportPoint, bool>> m_editing_mode_cache; // a support point and whether it is currently selected
 
     bool m_selection_rectangle_active = false;
@@ -499,12 +501,26 @@ private:
     Vec2d m_selection_rectangle_end_corner;
     bool m_ignore_up_event = false;
     bool m_combo_box_open = false;
+    bool m_unsaved_changes = false;
+    EState m_old_state = Off; // to be able to see that the gizmo has just been closed (see on_set_state)
 #if SLAGIZMO_IMGUI_MODAL
     bool m_show_modal = false;
 #endif
     int m_canvas_width;
     int m_canvas_height;
 
+    // Methods that do the model_object and editing cache synchronization,
+    // editing mode selection, etc:
+    enum {
+        AllPoints = -2,
+        NoPoints,
+    };
+    void select_point(int i);
+    void editing_mode_apply_changes();
+    void editing_mode_discard_changes();
+    void editing_mode_reload_cache();
+    void get_data_from_backend();
+
 protected:
     void on_set_state() override;
     void on_start_dragging(const GLCanvas3D::Selection& selection) override;
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index be1a364c4..ede2dd823 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -2232,7 +2232,7 @@ void Plater::priv::on_slicing_update(SlicingStatusEvent &evt)
         }
     }
     if (evt.status.flags & PrintBase::SlicingStatus::RELOAD_SLA_SUPPORT_POINTS) {
-        // Update SLA gizmo
+        // Update SLA gizmo  (reload_scene calls update_gizmos_data)
         q->canvas3D()->reload_scene(true);
     }
 }
diff --git a/src/slic3r/GUI/Preset.cpp b/src/slic3r/GUI/Preset.cpp
index 19626847f..ab6d3275a 100644
--- a/src/slic3r/GUI/Preset.cpp
+++ b/src/slic3r/GUI/Preset.cpp
@@ -457,9 +457,8 @@ const std::vector<std::string>& Preset::sla_print_options()
             "support_critical_angle",
             "support_max_bridge_length",
             "support_object_elevation",
-            "support_density_at_horizontal",
-            "support_density_at_45",
-            "support_minimal_z",
+            "support_points_density_relative",
+            "support_points_minimal_distance",
             "pad_enable",
             "pad_wall_thickness",
             "pad_wall_height",
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 28b7cd248..788276357 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -3202,9 +3202,8 @@ void TabSLAPrint::build()
     optgroup->append_single_option_line("support_max_bridge_length");
 
     optgroup = page->new_optgroup(_(L("Automatic generation")));
-    optgroup->append_single_option_line("support_density_at_horizontal");
-    optgroup->append_single_option_line("support_density_at_45");
-    optgroup->append_single_option_line("support_minimal_z");
+    optgroup->append_single_option_line("support_points_density_relative");
+    optgroup->append_single_option_line("support_points_minimal_distance");
 
     page = add_options_page(_(L("Pad")), "brick.png");
     optgroup = page->new_optgroup(_(L("Pad")));