diff --git a/src/OpenMesh/Apps/VDProgMesh/Synthesizer/VDPMSynthesizerViewerWidget.hh b/src/OpenMesh/Apps/VDProgMesh/Synthesizer/VDPMSynthesizerViewerWidget.hh
index b003ac0d..088d3ad0 100644
--- a/src/OpenMesh/Apps/VDProgMesh/Synthesizer/VDPMSynthesizerViewerWidget.hh
+++ b/src/OpenMesh/Apps/VDProgMesh/Synthesizer/VDPMSynthesizerViewerWidget.hh
@@ -106,7 +106,7 @@ public:
 
 public:
 
-  VDPMSynthesizerViewerWidget(QWidget* _parent=0, const char* _name=0);
+  explicit VDPMSynthesizerViewerWidget(QWidget* _parent=0, const char* _name=0);
 
   ~VDPMSynthesizerViewerWidget();
 
@@ -144,12 +144,12 @@ private:
 
   void update_viewing_parameters();
 
-  virtual void keyPressEvent(QKeyEvent* _event);
+  virtual void keyPressEvent(QKeyEvent* _event) override;
 
 protected:
 
   /// inherited drawing method
-  virtual void draw_scene(const std::string& _draw_mode);
+  virtual void draw_scene(const std::string& _draw_mode) override;
 
 public: