diff --git a/Polyhedron/demo/Polyhedron/Scene.cpp b/Polyhedron/demo/Polyhedron/Scene.cpp
index b8fc8164686..c9b2fbfdd73 100644
--- a/Polyhedron/demo/Polyhedron/Scene.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene.cpp
@@ -355,8 +355,6 @@ Scene::draw_aux(bool with_names, CGAL::Three::Viewer_interface* viewer)
                     viewer->glShadeModel(GL_SMOOTH);
                 else
                     viewer->glShadeModel(GL_FLAT);
-
-                item.contextual_changed();
                 if(viewer)
                     item.draw(viewer);
                 else
@@ -422,7 +420,6 @@ glDepthFunc(GL_LEQUAL);
                 }
             }
         }
-         item.contextual_changed();
         if(with_names) {
             viewer->glPopName();
         }
@@ -451,7 +448,6 @@ glDepthFunc(GL_LEQUAL);
                     item.draw_points();
             }
         }
-         item.contextual_changed();
         if(with_names) {
             viewer->glPopName();
         }
diff --git a/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.cpp b/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.cpp
index b9f7c257003..6a6f1392e4b 100644
--- a/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.cpp
@@ -353,9 +353,8 @@ Scene_implicit_function_item(Implicit_function_interface* f)
     texture = new Texture(grid_size_-1,grid_size_-1);
     blue_color_ramp_.build_blue();
     red_color_ramp_.build_red();
-    //
+    startTimer(0);
     //Generates an integer which will be used as ID for each buffer
-
     compute_min_max();
     compute_function_grid();
     double offset_x = (bbox().xmin + bbox().xmax) / 2;
@@ -583,15 +582,12 @@ Scene_implicit_function_item::invalidate_buffers()
     are_buffers_filled = false;
 }
 
-void Scene_implicit_function_item::contextual_changed()
-{
-    if(!frame_->isManipulated()) {
-        if(need_update_) {
-            compute_function_grid();
-            compute_vertices_and_texmap();
-            need_update_ = false;
-        }
-    }
+
+void Scene_implicit_function_item::timerEvent(QTimerEvent* /*event*/)
+{ // just handle deformation - paint like selection is handled in eventFilter()
+  if(need_update_) {
+    compute_function_grid();
+    compute_vertices_and_texmap();
+    need_update_= false;
+  }
 }
-
-
diff --git a/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.h b/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.h
index b3f2f2b2282..7c1109d2594 100644
--- a/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_implicit_function_item.h
@@ -69,11 +69,11 @@ public:
   virtual void draw_edges(CGAL::Three::Viewer_interface*) const;
 
   virtual QString toolTip() const;
-  virtual void contextual_changed();
   virtual void invalidate_buffers();
 public Q_SLOTS:
   void plane_was_moved() { need_update_ = true; }
   void compute_function_grid() const;
+  void timerEvent(QTimerEvent*);
 
 private:
   typedef qglviewer::Vec                  Point;
diff --git a/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.cpp b/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.cpp
index bb2272f99c5..794f89eb92a 100644
--- a/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.cpp
@@ -352,17 +352,6 @@ Scene_textured_polyhedron_item::invalidate_buffers()
     compute_bbox();
 }
 void
-Scene_textured_polyhedron_item::
-contextual_changed()
-{
-    prev_shading = cur_shading;
-    cur_shading = renderingMode();
-    if(prev_shading != cur_shading)
-    {
-        invalidate_buffers();
-    }
-}
-void
 Scene_textured_polyhedron_item::selection_changed(bool p_is_selected)
 {
     if(p_is_selected != is_selected)
diff --git a/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.h b/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.h
index 19d0b7eb1fb..c98da7864f1 100644
--- a/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_textured_polyhedron_item.h
@@ -28,7 +28,7 @@ public:
   virtual QString toolTip() const;
 
   // Indicate if rendering mode is supported
-  virtual bool supportsRenderingMode(RenderingMode m) const { return m != Splatting; }
+  virtual bool supportsRenderingMode(RenderingMode m) const { return (m != Splatting && m != PointsPlusNormals && m != Points && m != Gouraud ); }
   // Points/Wireframe/Flat/Gouraud OpenGL drawing in a display list
    void draw() const {}
   virtual void draw(CGAL::Three::Viewer_interface*) const;
@@ -45,7 +45,6 @@ public:
   void compute_bbox() const;
 
   virtual void invalidate_buffers();
-  virtual void contextual_changed();
   virtual void selection_changed(bool);
 
 private:
@@ -55,15 +54,15 @@ private:
   enum VAOs {
       Facets=0,
       Edges,
-      NbOfVaos = Edges+1
+      NbOfVaos
   };
   enum VBOs {
-      Facets_Vertices,
+      Facets_Vertices=0,
       Facets_Normals,
       Facets_Texmap,
-      Edges_Vertices = 0,
-      Edges_Texmap= 0,
-      NbOfVbos = Edges_Texmap+1
+      Edges_Vertices,
+      Edges_Texmap,
+      NbOfVbos
   };
 
   mutable std::vector<float> positions_lines;
diff --git a/Three/include/CGAL/Three/Scene_item.h b/Three/include/CGAL/Three/Scene_item.h
index 87120d70f0a..7e0b33803d8 100644
--- a/Three/include/CGAL/Three/Scene_item.h
+++ b/Three/include/CGAL/Three/Scene_item.h
@@ -291,8 +291,6 @@ public Q_SLOTS:
   virtual void invalidate_buffers();
   //!Setter for the color of the item. Calls invalidate_buffers() so the new color is applied.
   virtual void setColor(QColor c) { color_ = c; invalidate_buffers(); }
-  //!When invalidate_buffers() is not enough.
-  virtual void contextual_changed(){}
   //!Setter for the RGB color of the item. Calls setColor(QColor).
   //!@see setColor(QColor c)
   void setRbgColor(int r, int g, int b) { setColor(QColor(r, g, b)); }
@@ -396,16 +394,14 @@ protected:
   /*! Contains the previous RenderingMode.
    * This is used to determine if invalidate_buffers should be called or not
    * in certain cases.
-   * @see invalidate_buffers()
-   * @see contextual_changed()*/
+   * @see invalidate_buffers()*/
   RenderingMode prev_shading;
   /*! \todo replace it by RenderingMode().
    * \brief
    *  Contains the current RenderingMode.
    * This is used to determine if invalidate_buffers should be called or not
    * in certain cases.
-   * @see invalidate_buffers()
-   * @see contextual_changed()*/
+   * @see invalidate_buffers()*/
   RenderingMode cur_shading;
   //!Contains the size of the vector of VBOs
   int buffersSize;