sounds like a hardware/driver issue.


some gaming cards having redrawing issues with these applications, with that said, I am assuming you have a gaming desktop card, not a workstation card.


Long ago I had a issue similiar with my ATI 9800 Pro.. with applications over the Maya App not disappearing when minimized as well as editing Isoparms on Nurb surfaces..

Hope this helps:

Try minimizing and then bringing back the application for it to refresh the whole application drawing.

also try updating your video drivers.