From Martin Beckett, "I tested DJ's fix to stop flicker on Windows + Qt viewer on 2.6.7

It solves the problem on XP and Win7 on Qt 4.5 and 4.62
It isn't necessary on Linux (ubuntu 8.10/9.04 Qt 4.5/4.6.2) but doesn't cause any harm.
But I have #ifdef'ed it with WIN32. I can't test it on 64bit windows (not sure if x64 defines WIN32?)"

examples/osgviewerQT/QOSGWidget.cpp

@@ -91,6 +91,11 @@ class QOSGWidget : public QWidget
         osgViewer::GraphicsWindow* getGraphicsWindow() { return _gw.get(); }
         const osgViewer::GraphicsWindow* getGraphicsWindow() const { return _gw.get(); }
 
+#ifdef WIN32
+        // Prevent flicker on Windows Qt
+        QPaintEngine* paintEngine () const { return 0; }
+#endif
+
     protected:
 
         void init();