As stated in upstream bug report disabling Composite extension in xorg.conf solve temporary the issue. I'll try to apply the upstream patch too see if helps and I'll report a feedback
-- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/726369 Title: graphical glitches in menu and metacity (natty) _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp