diff --git a/src/osgQt/GraphicsWindowQt.cpp b/src/osgQt/GraphicsWindowQt.cpp
index e5762f218..d7343118a 100644
--- a/src/osgQt/GraphicsWindowQt.cpp
+++ b/src/osgQt/GraphicsWindowQt.cpp
@@ -342,7 +342,7 @@ bool GraphicsWindowQt::init( QWidget* parent, const QGLWidget* shareWidget, Qt::
         // WindowFlags
         Qt::WindowFlags flags = f | Qt::Window | Qt::CustomizeWindowHint;
         if ( _traits->windowDecoration )
-            flags |= Qt::WindowTitleHint | Qt::WindowMinMaxButtonsHint | Qt::WindowSystemMenuHint;
+            flags |= Qt::WindowTitleHint | Qt::WindowMinMaxButtonsHint | Qt::WindowSystemMenuHint | Qt::WindowCloseButtonHint;
 
         // create widget
         _widget = new GLWidget( traits2qglFormat( _traits ), parent, shareWidget, flags );