Focus on QDockWidget

I am using QDockWidget with Qt 4.5.3 and I am trying to find a way to render that a QDockWidget is having the mouse focus.
Currently when I am mouse clicking on a QDockWidget there is no change in the widget apperance to show that it has been clicked.
I have set the focus policy as follow:
dock->setFocusPolicy(Qt::ClickFocus);

Any help would be greatly appreciated

Lynn