https://bugs.freedesktop.org/show_bug.cgi?id=61182
--- Comment #50 from Marco Trevisan (Treviño) mail@3v1n0.net --- (In reply to comment #48)
Noticed the same issue in unity (compiz, actually) as soon as the opengl plugin is loaded.
It seems to happen mostly in multi-monitor: http://paste.ubuntu.com/5661055/
FYI, Compiz fix is in https://code.launchpad.net/~3v1n0/compiz/msaa-configs-ignore/+merge/163550 and tracked by bug https://bugs.launchpad.net/compiz/+bug/1174495