QGLWidget resize not working

Hi,
I have an issue with resizing my openGL widget class (QGLWidget).
The widget is rendered in a dock widget but upon resizing the window the graphics display incorrectly. If a move the window position however the viewport resizes and all is fine.

Also i've added a context menu to the window and when it renders, focus seems to be lost and the opengL graphic display breaks.

I've overriden initializeGL, paintGL and resizeGL..

Any help much appreciated.. ?

Thanks, M