diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index c5b8bd436..08989089d 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -1025,6 +1025,10 @@ sub increase {
     } else {
         $self->update;
     }
+
+#========================================================================================================================    
+    $self->selection_changed;  # refresh info (size, volume etc.)
+#========================================================================================================================        
     $self->schedule_background_process;
 }
 
@@ -2223,17 +2227,30 @@ sub selection_changed {
     if ($self->{htoolbar}) {
         # On OSX or Linux
         $self->{htoolbar}->EnableTool($_, $have_sel)
-            for (TB_REMOVE, TB_MORE, TB_FEWER, TB_45CW, TB_45CCW, TB_SCALE, TB_SPLIT, TB_CUT, TB_SETTINGS);
+#===================================================================================================================================================            
+            for (TB_REMOVE, TB_MORE, TB_45CW, TB_45CCW, TB_SCALE, TB_SPLIT, TB_CUT, TB_SETTINGS);
+#            for (TB_REMOVE, TB_MORE, TB_FEWER, TB_45CW, TB_45CCW, TB_SCALE, TB_SPLIT, TB_CUT, TB_SETTINGS);
+#===================================================================================================================================================            
             
 #===================================================================================================================================================            
         $self->{htoolbar}->EnableTool(TB_LAYER_EDITING, $layers_height_allowed);
+
+        if ($have_sel) {
+            my $model_object = $self->{model}->objects->[$obj_idx];
+            $self->{htoolbar}->EnableTool(TB_FEWER, $model_object->instances_count > 1);
+        } else {
+            $self->{htoolbar}->EnableTool(TB_FEWER, 0);
+        }
 #===================================================================================================================================================
             
     } else {
         # On MSW
         my $method = $have_sel ? 'Enable' : 'Disable';
         $self->{"btn_$_"}->$method
-            for grep $self->{"btn_$_"}, qw(remove increase decrease rotate45cw rotate45ccw changescale split cut settings);
+#===================================================================================================================================================
+            for grep $self->{"btn_$_"}, qw(remove increase rotate45cw rotate45ccw changescale split cut settings);
+#            for grep $self->{"btn_$_"}, qw(remove increase decrease rotate45cw rotate45ccw changescale split cut settings);
+#===================================================================================================================================================
             
 #===================================================================================================================================================
         if ($layers_height_allowed) {
@@ -2241,6 +2258,17 @@ sub selection_changed {
         } else {
             $self->{"btn_layer_editing"}->Disable;
         }
+
+        if ($have_sel) {
+            my $model_object = $self->{model}->objects->[$obj_idx];
+            if ($model_object->instances_count > 1) {
+                $self->{"btn_decrease"}->Enable;
+            } else {
+                $self->{"btn_decrease"}->Disable;
+            }            
+        } else {
+            $self->{"btn_decrease"}->Disable;
+        }
 #===================================================================================================================================================
     }
     
@@ -2250,6 +2278,11 @@ sub selection_changed {
     }
     
     Slic3r::GUI::_3DScene::enable_toolbar_item($self->{canvas3D}, "layersediting", $layers_height_allowed);
+    
+    if ($have_sel) {
+        my $model_object = $self->{model}->objects->[$obj_idx];
+        Slic3r::GUI::_3DScene::enable_toolbar_item($self->{canvas3D}, "fewer", $model_object->instances_count > 1);
+    }
 #===================================================================================================================================================
     
     if ($self->{object_info_size}) { # have we already loaded the info pane?
diff --git a/xs/src/slic3r/GUI/GLCanvas3D.cpp b/xs/src/slic3r/GUI/GLCanvas3D.cpp
index 7c8bf4665..414cad8e5 100644
--- a/xs/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/xs/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1692,6 +1692,9 @@ GLCanvas3D::GLCanvas3D(wxGLCanvas* canvas)
     : m_canvas(canvas)
     , m_context(nullptr)
     , m_timer(nullptr)
+//###################################################################################################################################
+    , m_toolbar(*this)
+//###################################################################################################################################
     , m_config(nullptr)
     , m_print(nullptr)
     , m_model(nullptr)
@@ -2798,7 +2801,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     m_layers_editing.last_object_id = layer_editing_object_idx;
     bool gizmos_overlay_contains_mouse = m_gizmos.overlay_contains_mouse(*this, m_mouse.position);
 //###################################################################################################################################
-    int toolbar_contains_mouse = m_toolbar.contains_mouse(*this, m_mouse.position);
+    int toolbar_contains_mouse = m_toolbar.contains_mouse(m_mouse.position);
 //###################################################################################################################################
 
     if (evt.Entering())
@@ -2823,7 +2826,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     else if (evt.LeftDClick() && (toolbar_contains_mouse != -1))
     {
         m_toolbar_action_running = true;
-        m_toolbar.do_action((unsigned int)toolbar_contains_mouse, *this);
+        m_toolbar.do_action((unsigned int)toolbar_contains_mouse);
     }
 //###################################################################################################################################
     else if (evt.LeftDown() || evt.RightDown())
@@ -2868,7 +2871,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
         else if (toolbar_contains_mouse != -1)
         {
             m_toolbar_action_running = true;
-            m_toolbar.do_action((unsigned int)toolbar_contains_mouse, *this);
+            m_toolbar.do_action((unsigned int)toolbar_contains_mouse);
         }
 //###################################################################################################################################
         else
@@ -2927,9 +2930,20 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 }
                 else if (evt.RightDown())
                 {
-                    // if right clicking on volume, propagate event through callback
-                    if (m_volumes.volumes[volume_idx]->hover)
-                        m_on_right_click_callback.call(pos.x, pos.y);
+//###################################################################################################################################
+                    // forces a frame render to ensure that m_hover_volume_id is updated even when the user right clicks while
+                    // the context menu is already shown, ensuring it to disappear if the mouse is outside any volume
+                    m_mouse.position = Pointf((coordf_t)pos.x, (coordf_t)pos.y);
+                    render();
+                    if (m_hover_volume_id != -1)
+                    {
+//###################################################################################################################################
+                        // if right clicking on volume, propagate event through callback (shows context menu)
+                        if (m_volumes.volumes[volume_idx]->hover)
+                            m_on_right_click_callback.call(pos.x, pos.y);
+//###################################################################################################################################
+                    }
+//###################################################################################################################################
                 }
             }
         }
@@ -3128,7 +3142,10 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             
             _on_move(volume_idxs);
         }
-        else if (!m_mouse.dragging && (m_hover_volume_id == -1) && !gizmos_overlay_contains_mouse && !m_gizmos.is_dragging() && !is_layers_editing_enabled())
+//#############################################################################################################################################################################
+        else if (evt.LeftUp() && !m_mouse.dragging && (m_hover_volume_id == -1) && !gizmos_overlay_contains_mouse && !m_gizmos.is_dragging() && !is_layers_editing_enabled())
+//        else if (!m_mouse.dragging && (m_hover_volume_id == -1) && !gizmos_overlay_contains_mouse && !m_gizmos.is_dragging() && !is_layers_editing_enabled())
+//#############################################################################################################################################################################
         {
             // deselect and propagate event through callback
 //###################################################################################################################################
@@ -3780,7 +3797,7 @@ void GLCanvas3D::_picking_pass() const
             m_gizmos.reset_all_states();
 
 //###################################################################################################################################
-        m_toolbar.update_hover_state(const_cast<GLCanvas3D&>(*this), pos);
+        m_toolbar.update_hover_state(pos);
 //###################################################################################################################################
     }
 }
@@ -4034,7 +4051,7 @@ void GLCanvas3D::_render_gizmo() const
 //###################################################################################################################################
 void GLCanvas3D::_render_toolbar() const
 {
-    m_toolbar.render(*this, m_mouse.position);
+    m_toolbar.render(m_mouse.position);
 }
 //###################################################################################################################################
 
diff --git a/xs/src/slic3r/GUI/GLToolbar.cpp b/xs/src/slic3r/GUI/GLToolbar.cpp
index e6e9eeac8..c425164a2 100644
--- a/xs/src/slic3r/GUI/GLToolbar.cpp
+++ b/xs/src/slic3r/GUI/GLToolbar.cpp
@@ -11,7 +11,7 @@
 namespace Slic3r {
 namespace GUI {
 
-    GLToolbarItem::GLToolbarItem(EType type, const std::string& name, const std::string& tooltip, bool is_toggable, PerlCallback* action_callback)
+GLToolbarItem::GLToolbarItem(EType type, const std::string& name, const std::string& tooltip, bool is_toggable, PerlCallback* action_callback)
     : m_type(type)
     , m_state(Disabled)
     , m_name(name)
@@ -82,6 +82,16 @@ bool GLToolbarItem::is_enabled() const
     return m_state != Disabled;
 }
 
+bool GLToolbarItem::is_hovered() const
+{
+    return (m_state == Hover) || (m_state == HoverPressed);
+}
+
+bool GLToolbarItem::is_pressed() const
+{
+    return (m_state == Pressed) || (m_state == HoverPressed);
+}
+
 bool GLToolbarItem::is_toggable() const
 {
     return m_is_toggable;
@@ -92,8 +102,9 @@ bool GLToolbarItem::is_separator() const
     return m_type == Separator;
 }
 
-GLToolbar::GLToolbar()
-    : m_enabled(false)
+GLToolbar::GLToolbar(GLCanvas3D& parent)
+    : m_parent(parent)
+    , m_enabled(false)
     , m_textures_scale(1.0f)
     , m_offset_y(5.0f)
     , m_gap_x(2.0f)
@@ -156,7 +167,7 @@ void GLToolbar::enable_item(const std::string& name)
 {
     for (GLToolbarItem* item : m_items)
     {
-        if (item->get_name() == name)
+        if ((item->get_name() == name) && (item->get_state() == GLToolbarItem::Disabled))
         {
             item->set_state(GLToolbarItem::Normal);
             return;
@@ -181,18 +192,18 @@ bool GLToolbar::is_item_pressed(const std::string& name) const
     for (GLToolbarItem* item : m_items)
     {
         if (item->get_name() == name)
-            return (item->get_state() == GLToolbarItem::Pressed) || (item->get_state() == GLToolbarItem::HoverPressed);
+            return item->is_pressed();
     }
 
     return false;
 }
 
-void GLToolbar::update_hover_state(GLCanvas3D& canvas, const Pointf& mouse_pos)
+void GLToolbar::update_hover_state(const Pointf& mouse_pos)
 {
     if (!m_enabled)
         return;
 
-    float cnv_w = (float)canvas.get_canvas_size().get_width();
+    float cnv_w = (float)m_parent.get_canvas_size().get_width();
     float width = _get_total_width();
     float left = 0.5f * (cnv_w - width);
     float top = m_offset_y;
@@ -256,15 +267,15 @@ void GLToolbar::update_hover_state(GLCanvas3D& canvas, const Pointf& mouse_pos)
         }
     }
 
-    canvas.set_tooltip(tooltip);
+    m_parent.set_tooltip(tooltip);
 }
 
-int GLToolbar::contains_mouse(const GLCanvas3D& canvas, const Pointf& mouse_pos) const
+int GLToolbar::contains_mouse(const Pointf& mouse_pos) const
 {
     if (!m_enabled)
         return -1;
 
-    float cnv_w = (float)canvas.get_canvas_size().get_width();
+    float cnv_w = (float)m_parent.get_canvas_size().get_width();
     float width = _get_total_width();
     float left = 0.5f * (cnv_w - width);
     float top = m_offset_y;
@@ -293,12 +304,12 @@ int GLToolbar::contains_mouse(const GLCanvas3D& canvas, const Pointf& mouse_pos)
     return -1;
 }
 
-void GLToolbar::do_action(unsigned int item_id, GLCanvas3D& canvas)
+void GLToolbar::do_action(unsigned int item_id)
 {
     if (item_id < (unsigned int)m_items.size())
     {
         GLToolbarItem* item = m_items[item_id];
-        if ((item != nullptr) && !item->is_separator() && item->is_enabled())
+        if ((item != nullptr) && !item->is_separator() && item->is_hovered())
         {
             if (item->is_toggable())
             {
@@ -308,26 +319,26 @@ void GLToolbar::do_action(unsigned int item_id, GLCanvas3D& canvas)
                 else if (state == GLToolbarItem::HoverPressed)
                     item->set_state(GLToolbarItem::Hover);
 
-                canvas.render();
+                m_parent.render();
                 item->do_action();
             }
             else
             {
                 item->set_state(GLToolbarItem::HoverPressed);
-                canvas.render();
+                m_parent.render();
                 item->do_action();
                 if (item->get_state() != GLToolbarItem::Disabled)
                 {
-                    // the item may get disabled during the action, if not, set it to normal state
+                    // the item may get disabled during the action, if not, set it back to hover state
                     item->set_state(GLToolbarItem::Hover);
-                    canvas.render();
+                    m_parent.render();
                 }
             }
         }
     }
 }
 
-void GLToolbar::render(const GLCanvas3D& canvas, const Pointf& mouse_pos) const
+void GLToolbar::render(const Pointf& mouse_pos) const
 {
     if (!m_enabled || m_items.empty())
         return;
@@ -337,9 +348,9 @@ void GLToolbar::render(const GLCanvas3D& canvas, const Pointf& mouse_pos) const
     ::glPushMatrix();
     ::glLoadIdentity();
 
-    float cnv_w = (float)canvas.get_canvas_size().get_width();
-    float cnv_h = (float)canvas.get_canvas_size().get_height();
-    float zoom = canvas.get_camera_zoom();
+    float cnv_w = (float)m_parent.get_canvas_size().get_width();
+    float cnv_h = (float)m_parent.get_canvas_size().get_height();
+    float zoom = m_parent.get_camera_zoom();
     float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
 
     float width = _get_total_width();
diff --git a/xs/src/slic3r/GUI/GLToolbar.hpp b/xs/src/slic3r/GUI/GLToolbar.hpp
index e5c8f9fb8..d157f2a3b 100644
--- a/xs/src/slic3r/GUI/GLToolbar.hpp
+++ b/xs/src/slic3r/GUI/GLToolbar.hpp
@@ -66,6 +66,9 @@ public:
     void do_action();
 
     bool is_enabled() const;
+    bool is_hovered() const;
+    bool is_pressed() const;
+
     bool is_toggable() const;
     bool is_separator() const;
 };
@@ -85,6 +88,7 @@ public:
 private:
     typedef std::vector<GLToolbarItem*> ItemsList;
 
+    GLCanvas3D& m_parent;
     bool m_enabled;
     ItemsList m_items;
 
@@ -94,7 +98,7 @@ private:
     float m_separator_x;
 
 public:
-    GLToolbar();
+    explicit GLToolbar(GLCanvas3D& parent);
 
     bool is_enabled() const;
     void set_enabled(bool enable);
@@ -112,14 +116,14 @@ public:
 
     bool is_item_pressed(const std::string& name) const;
 
-    void update_hover_state(GLCanvas3D& canvas, const Pointf& mouse_pos);
+    void update_hover_state(const Pointf& mouse_pos);
 
     // returns the id of the item under the given mouse position or -1 if none
-    int contains_mouse(const GLCanvas3D& canvas, const Pointf& mouse_pos) const;
+    int contains_mouse(const Pointf& mouse_pos) const;
 
-    void do_action(unsigned int item_id, GLCanvas3D& canvas);
+    void do_action(unsigned int item_id);
 
-    void render(const GLCanvas3D& canvas, const Pointf& mouse_pos) const;
+    void render(const Pointf& mouse_pos) const;
 
 private:
     float _get_total_width() const;