diff --git a/Polyhedron/demo/Polyhedron/Plugins/Display/Display_property_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Display/Display_property_plugin.cpp
index b6295f78d01..39f68c20b78 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Display/Display_property_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Display/Display_property_plugin.cpp
@@ -313,7 +313,7 @@ private Q_SLOTS:
     }
   }
 
-  void closure()
+  void closure()Q_DECL_OVERRIDE
   {
     dock_widget->hide();
   }
diff --git a/Three/demo/Three/Example_plugin/Dock_widget_plugin.cpp b/Three/demo/Three/Example_plugin/Dock_widget_plugin.cpp
index 0a2ad1b2e90..09223ccb042 100644
--- a/Three/demo/Three/Example_plugin/Dock_widget_plugin.cpp
+++ b/Three/demo/Three/Example_plugin/Dock_widget_plugin.cpp
@@ -85,7 +85,7 @@ private Q_SLOTS:
   }
   //! [action]
   //! [closure]
-  void closure()
+  void closure()Q_DECL_OVERRIDE
   {
     dock_widget->hide();
   }