Odd experience w/not responding programs.

Sometimes when a program hangs for a bit, but eventually recovers itself, the window looks messed up like the skin is malfunctioning in some way. My firefox will sometimes lock up for a few seconds while loading a really heavy web site, or an explorer window while transferring a large amount of files, etc. 

In order to get the window to look normal again, even after it starts responding again (its just seconds), I have to grab it and drag it somewhere. Then it redraws and all is well.

Do you think this is just a limitation of my system?  My hardware gets a 3.5 score in windows experience and I verified that all my drivers are up to date. This didn't used to happen before I installed WindowBlinds (6.4).

Thanks.