Comment 6 for bug 365182

BTW...in the screen shot named "snapshot2.png" that was posted above, the flickering black rectangles that are representative of the problem that I observe are shown near the bottom of the captured Firefox screen.

What is also interesting is that I installed Kubuntu 9.04 on three computers around the same time. Two computers are actually identical in terms of hardware. I get this flickering black rectangle problem only on one computer. On the affected computer, I did a fresh install of Kubuntu 9.04 beta 4 and upgraded to the final release when it came out. On the other two computers, I either did a fresh install of the final release, or I did an upgrade install from Kubuntu 8.10. Maybe this is unrelated.