This seems to be a regression caused by compiz r3623 (reverting that revision makes the gap disappear) and is not Unity related (this can be reproduced by just loading core and decor plugins).
** Package changed: unity (Ubuntu) => compiz (Ubuntu) ** Also affects: compiz Importance: Undecided Status: New ** Changed in: compiz Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1140505 Title: [regression-r3623] Wallpaper bleeds through on top right when a window is opened maximized To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/1140505/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs