QDialog not closing properly

I have a dialog popup for the user to select some options, if the user clicks OK, the accept signal is caught.
When the signal is caught, a new thread is created to handle some computations, the program then continuous to run through a progress bar.
The problem is that a gray area is left behind on the screen after the dialog closed (accepted).

I have attached 2 screenshots showing the problem.
screen0 – die dialog before OK is clicked
screen1 – right after OK was clicked

Can anyone help?

http://foxhat.org/images/screen0.jpg

http://foxhat.org/images/screen1.jpg

What happens if you do a rePaint() on the dialog?

You are somewhere preventing the events from being processed. Most likely your "thread" is not really a thread and it blocks the main event loop.

It turned out to be my graphic card drivers. Apparently this happens often with faulty graphic cards (or drivers). But thanks anyway for your input.