I'm seeing this on a T40 with a Radeon 7500, largely in totem. See also bugs #38198 and #44586. It is likely that this was fixed in version 6.5.8.0 of the ati driver: http://lists.freedesktop.org/archives/xorg/2006-April/014965.html
-- [Dapper] Buttons have graphics artifacts with Human theme https://launchpad.net/bugs/43904 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
