This issue has to do with the Adobe OS Widget Library (OWL), and is something that can be easily reproduced.
OWL is effectively a skin over the top of the Windows API, and doesn't seem to be consistently covering the Photoshop API. I've seen this issue with Illustrator CS4 as well, but it's harder to reproduce.
To reproduce, open a modal dialog (like Image Size or Levels adjustment). It's not entirely consistent, but happens most of the time.
Here are a couple of screen shots:
<http://www.pixentral.com/show.php?picture=1GZyafDMFggobQ5gpky0vTAykAb39>
<http://www.pixentral.com/show.php?picture=1vvFITWyhtgyCGvFQP7u4zfNl2BG>
<http://www.pixentral.com/show.php?picture=1amw63uKVH1vlMz3RBWNSDhEi1cmwh1>
I would also suggest downloading the latest directx 9c, .net 3.5, and c++ for 2008. A good defrag would help too.
Also if you have ATI CCC try unchecking triple buffering located in 3D all settings.