Phantom boxes drawn with KDE 4.2 + 180.x driver
I'm seeing a problem with my installation - EVGA 8800GT card, driver 180.44 (although I've seen this with all the 180 series), Kubuntu 9.04, KDE 4.2.2 (but again, seen on earlier KDE 4.2.x releases.) Sometime when switching windows, a box border or part of a box border is drawn in the window. The box doesn't match up with the window borders or anything obvious on the screen. I can reproduce it pretty easily by overlapping two windows (for example a Konsole and a file manager window) and moving the mouse slowly between them (with focus-follows-mouse turned on.) The boxes show up and then disappear as the mouse moves. If I keep repeating, eventually I won't see the boxes any more. Sometimes if I'm running an app in Wine (like World of Warcraft) sometimes I'll see the same type of box appear apparently at random. Mplayer with vdpau has also shown these boxes.
I have composite turned on in KDE, with a lot of the effects (including wobbly windows) turned on. Turning off all effects seems to solve the problem.
Has anyone seen anything similar? Is there any configuration setting I need to give to improve the situation?