diff --git a/Polyhedron/demo/Polyhedron/Polyhedron_demo_hole_filling_plugin.cpp b/Polyhedron/demo/Polyhedron/Polyhedron_demo_hole_filling_plugin.cpp
index 25aa7fb9c84..fba23227f43 100644
--- a/Polyhedron/demo/Polyhedron/Polyhedron_demo_hole_filling_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Polyhedron_demo_hole_filling_plugin.cpp
@@ -36,22 +36,6 @@
 
 #include <boost/function_output_iterator.hpp>
 
-// To get close event from dock widget (close event in this case means pressing x button)
-class Dock_widget_event_filter : public QObject
-{
-  Q_OBJECT
-public:
-signals:
-  void dock_widget_closed();
-protected:
-  bool eventFilter(QObject *, QEvent *event) {
-    if(event->type() == QEvent::Close) {
-      emit dock_widget_closed();
-    }
-    return false;
-  }
-};
-
 // Class for visualizing holes in a polyhedron
 // provides mouse selection functionality
 class Q_DECL_EXPORT Scene_polylines_collection : public Scene_item
@@ -330,7 +314,13 @@ public slots:
   void item_about_to_be_destroyed(Scene_item*);
   void item_changed_polylines_collection();
   void dock_widget_closed();
-
+protected:
+  bool eventFilter(QObject *, QEvent *event) {
+    if(event->type() == QEvent::Close) {
+      dock_widget_closed();
+    }
+    return false;
+  }
 private:
   struct Nop_functor {
     template<class T>
@@ -345,7 +335,6 @@ private:
 
   QDockWidget* dock_widget;
   Ui::HoleFilling ui_widget;
-  Dock_widget_event_filter filter;
 
   // hold created facet for accept reject functionality
   std::vector<Polyhedron::Facet_handle> new_facets; 
@@ -390,7 +379,7 @@ void Polyhedron_demo_hole_filling_plugin::init(QMainWindow* mainWindow,
 
   dock_widget = new QDockWidget("Hole Filling", mw);
   dock_widget->setVisible(false);
-  dock_widget->installEventFilter(&filter);
+  dock_widget->installEventFilter(this);
 
   ui_widget.setupUi(dock_widget);
   ui_widget.Accept_button->setVisible(false);
@@ -398,7 +387,6 @@ void Polyhedron_demo_hole_filling_plugin::init(QMainWindow* mainWindow,
 
   mw->addDockWidget(Qt::LeftDockWidgetArea, dock_widget);
 
-  connect(&filter, SIGNAL(dock_widget_closed()), this, SLOT(dock_widget_closed()));
   connect(ui_widget.Visualize_holes_button,  SIGNAL(clicked()), this, SLOT(on_Visualize_holes_button()));  
   connect(ui_widget.Fill_selected_holes_button,  SIGNAL(clicked()), this, SLOT(on_Fill_selected_holes_button())); 
   connect(ui_widget.Fill_all_holes_button,  SIGNAL(clicked()), this, SLOT(on_Fill_all_holes_button()));