My problem is that since upgrading to 4.7.1 kWin draws the screen fine, but then after a minute or two certain areas of the screen get bleed thru of a rainbow of color eventually turning the area black. This problem quickly expands to other areas of the desktop. Panels, windows, title bars, toolbar buttons, etc..

Wish I could furnish a screenshot but I can't yet. I've read up and I think it might be in the .config file; possibly in a /home/user/.config file? I'm not on my system so I'll check it when I get home.

I've deleted the .kde (.kde4 only -on my system, Chakra). I've made sure to delete it with the graphical desktop killed... still no fix.

I noticed it started the day I upgraded (last week, finally!) I was playing around with the window title-bar themes. I switched to a new theme. then the display (starting with the themed bar) started looking "glitchy." No problems up until that point. I switched back to the standard 'oxygen' theme and 'air' theme... but the display bug remained and got worse. Spread to the entire desktop of applications..... but curiously enough it does NOT effect the desktop wallpaper itself.

I have something like this as well (Kubuntu Natty, KDE 4.7.1): the screen starts to draw funny under certain dual monitor conditions. Under clone mode everything seems to be fine. But if I try to put the TV screen besides the laptop screen, I cannot – I see the tv screen and it extends to 1/3 of my laptop screen as well. I can move the mouse to the rest 2/3rds of the screen of laptop, but it is all black, and I cannot put any window in there. And if I put the tv screen below the laptop screen, the laptop screen behaves like what you described above. If I manage to go back to single screen (laptop), everything goes back to normal.