I'm pretty sure it is a bug introduced by Unity. This doesn't happen when i use Gnome 3 or Cinnamon on my machine, Unity 3D only.
Ubuntu 12.04 x64, NVIDIA Quadro FX 3450/4000 SDI, NVidia driver 295.40. ** Package changed: compiz (Ubuntu) => unity (Ubuntu) -- 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/990069 Title: Alt-Tab in Unity 12.04 brings up white window for multiple instances To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/990069/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : [email protected] Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp
