Comment 4 for bug 109550

Just a quick update: I did get the black box issue to stop in KDE with the tip you gave. I started application after application and no black boxes appeared. Performance of beryl is notably suckier, but it's a small price to pay to rid myself of the blacked-out applications of death.

So it's not just gnome your tip works in. Interestingly, I was sort of able to reproduce the problem, but it wasn't quite the same. I got a white box in Firefox with, like, 5 other instances open. So I don't know what to make of that.... But the situation is vastly improved.

Thanks again for the tip.