I get this as well (e.g., open Sound Menu > Sound Settings..., and minimize that window). According to https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/709461/comments/145 this bug will be solved by an xserver upload soon.
-- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/850458 Title: Minimizing windows in Oneiric cause invisible windows To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/850458/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : [email protected] Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp

