Using Option "XaaNoOffscreenPixmaps" in device section of xorg.conf file solved the problem for me. I'm using a ATI Radeon IGP345M with radeon driver.
-- Cairo and ATI RENDER extension cause scrambled buttons in UbuntuLooks https://launchpad.net/bugs/34435 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
