diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
index c2fd5f390b9..c039393b1e4 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
@@ -62,7 +62,8 @@ Scene_polyhedron_item::Scene_polyhedron_item()
     poly(new Polyhedron),
     show_only_feature_edges_m(false),
     facet_picking_m(false),
-    erase_next_picked_facet_m(false)
+    erase_next_picked_facet_m(false),
+    plugin_has_set_color_vector_m(false)
 {
   //init();
 }
@@ -72,7 +73,8 @@ Scene_polyhedron_item::Scene_polyhedron_item(Polyhedron* const p)
     poly(p),
     show_only_feature_edges_m(false),
     facet_picking_m(false),
-    erase_next_picked_facet_m(false)
+    erase_next_picked_facet_m(false),
+    plugin_has_set_color_vector_m(false)
 {
   init();
 }
@@ -82,7 +84,8 @@ Scene_polyhedron_item::Scene_polyhedron_item(const Polyhedron& p)
     poly(new Polyhedron(p)),
     show_only_feature_edges_m(false),
     facet_picking_m(false),
-    erase_next_picked_facet_m(false)
+    erase_next_picked_facet_m(false),
+    plugin_has_set_color_vector_m(false)
 {
   init();
 }
@@ -108,17 +111,20 @@ init()
 {
   typedef Polyhedron::Facet_iterator Facet_iterator;
   
-  // Fill indices map and get max subdomain value
-  int max = 0;
-  for(Facet_iterator fit = poly->facets_begin(), end = poly->facets_end() ;
-      fit != end; ++fit)
+  if ( !plugin_has_set_color_vector_m )
   {
-    max = (std::max)(max, fit->patch_id());
+    // Fill indices map and get max subdomain value
+    int max = 0;
+    for(Facet_iterator fit = poly->facets_begin(), end = poly->facets_end() ;
+        fit != end; ++fit)
+    {
+      max = (std::max)(max, fit->patch_id());
+    }
+    
+    colors_.clear();
+    compute_color_map(this->color(), max + 1, 
+                      std::back_inserter(colors_));
   }
-  
-  colors_.clear();
-  compute_color_map(this->color(), max + 1, 
-                    std::back_inserter(colors_));
 }
 
 
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
index 6785166c772..be73578f0e3 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
@@ -51,7 +51,8 @@ public:
   bool isEmpty() const;
   Bbox bbox() const;
   std::vector<QColor>& color_vector() {return colors_;}
-
+  void set_color_vector_read_only(bool on_off) {plugin_has_set_color_vector_m=on_off;}
+  
 public slots:
   virtual void changed();
   void show_only_feature_edges(bool);
@@ -85,6 +86,8 @@ private:
   bool show_only_feature_edges_m;
   bool facet_picking_m;
   bool erase_next_picked_facet_m;
+  //the following variable is used to indicate if the color vector must not be automatically updated.
+  bool plugin_has_set_color_vector_m;
 }; // end class Scene_polyhedron_item
 
 #endif // SCENE_POLYHEDRON_ITEM_H