If Daniel's fix (comment #8) is a workaround, then it's clearly a bug in xserver-xorg-video-intel. Added accordingly. Might be worth including in the Ubuntu GNOME staging ppa.
** Also affects: xserver-xorg-video-intel (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1378188 Title: strange shadow rendered where client-side decorations are used To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-gnome/+bug/1378188/+subscriptions _______________________________________________ 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