diff --git a/src/OpenGl/OpenGl_CappingAlgo.cxx b/src/OpenGl/OpenGl_CappingAlgo.cxx
index 61206dd8b1..a729da3620 100755
--- a/src/OpenGl/OpenGl_CappingAlgo.cxx
+++ b/src/OpenGl/OpenGl_CappingAlgo.cxx
@@ -228,7 +228,5 @@ Standard_Boolean OpenGl_CappingAlgoFilter::ShouldRender (const Handle(OpenGl_Wor
     return Standard_False;
   }
 
-  const OpenGl_PrimitiveArray* aPArray = dynamic_cast<const OpenGl_PrimitiveArray*> (theGlElement);
-  return aPArray != NULL
-      && aPArray->IsFillDrawMode();
+  return theGlElement->IsFillDrawMode();
 }
diff --git a/src/OpenGl/OpenGl_Element.hxx b/src/OpenGl/OpenGl_Element.hxx
index 74890eeb94..1df5afec69 100644
--- a/src/OpenGl/OpenGl_Element.hxx
+++ b/src/OpenGl/OpenGl_Element.hxx
@@ -54,6 +54,11 @@ public:
     theElement = NULL;
   }
 
+public:
+
+  //! Return TRUE if primitive type generates shaded triangulation (to be used in filters).
+  virtual Standard_Boolean IsFillDrawMode() const { return false; }
+
 public:
 
   //! Render element if it passes the filtering procedure. This method should
diff --git a/src/OpenGl/OpenGl_LayerList.cxx b/src/OpenGl/OpenGl_LayerList.cxx
index eddee5b10c..51dbc606c7 100644
--- a/src/OpenGl/OpenGl_LayerList.cxx
+++ b/src/OpenGl/OpenGl_LayerList.cxx
@@ -825,9 +825,7 @@ Standard_Boolean OpenGl_LayerList::OpenGl_OpaqueFilter::ShouldRender (const Hand
     return Standard_False;
   }
 
-  const OpenGl_PrimitiveArray* aPArray = dynamic_cast<const OpenGl_PrimitiveArray*> (theGlElement);
-  if (aPArray == NULL
-  || !aPArray->IsFillDrawMode())
+  if (!theGlElement->IsFillDrawMode())
   {
     return Standard_True;
   }
@@ -856,9 +854,7 @@ Standard_Boolean OpenGl_LayerList::OpenGl_TransparentFilter::ShouldRender (const
     return Standard_False;
   }
 
-  const OpenGl_PrimitiveArray* aPArray = dynamic_cast<const OpenGl_PrimitiveArray*> (theGlElement);
-  if (aPArray == NULL
-  || !aPArray->IsFillDrawMode())
+  if (!theGlElement->IsFillDrawMode())
   {
     return dynamic_cast<const OpenGl_AspectFace*> (theGlElement) != NULL;
   }
diff --git a/src/OpenGl/OpenGl_PrimitiveArray.hxx b/src/OpenGl/OpenGl_PrimitiveArray.hxx
index 5f1fa934c9..ddeff49591 100644
--- a/src/OpenGl/OpenGl_PrimitiveArray.hxx
+++ b/src/OpenGl/OpenGl_PrimitiveArray.hxx
@@ -53,10 +53,10 @@ public:
   Standard_EXPORT virtual ~OpenGl_PrimitiveArray();
 
   //! Render primitives to the window
-  Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
+  Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const Standard_OVERRIDE;
 
   //! Release OpenGL resources (VBOs)
-  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext) Standard_OVERRIDE;
 
   //! Return true if VBOs initialization has been performed.
   //! VBO initialization is performed during first Render() call.
@@ -70,7 +70,7 @@ public:
   GLint DrawMode() const { return myDrawMode; }
 
   //! Return TRUE if primitive type generates shaded triangulation.
-  Standard_Boolean IsFillDrawMode() const { return myIsFillType; }
+  virtual Standard_Boolean IsFillDrawMode() const Standard_OVERRIDE { return myIsFillType; }
 
   //! @return indices array
   const Handle(Graphic3d_IndexBuffer)& Indices() const { return myIndices; }