I also have this bug and it happens when switching windows via mouse click, Alt-Tab, or any of the various Launcher methods. I also have a Nvidia graphics card 8400GS. I have no idea where to begins figuring out which package is causing whindows to go white when brought into or out of focus. I suspect compiz or the Launcher being the root cause but all I can do is confirm that is happens. I have three screenshots of it. One is during window selection after clicking on the Programs icon in the Launcher with multiple windows open. The second shows VLC completely white while out of focus and playing a video. The third picture shows a terminal window open in focus completely white after clicking it's icon on the Launcher.
** Attachment added: "all three screenshots in one" https://bugs.launchpad.net/ubuntu/+bug/990069/+attachment/3114061/+files/screenshots.jpg -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to 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/+bug/990069/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs