I installed Ubuntu 2011.04 from scratch a few hours ago. At first Firefox was working perfectly. Then I selected "Static application switcher" in the Compiz configuration.

From that time, whenever I press ALT-TAB, Firefox's display is frozen. As hinted by the changing mouse cursor, I can click on link and select text, but I can not see it.

If I restart Firefox or simply unmaximize/remaximize it, the problem is gone, until the next ALT-TAB.

What's going wrong? How to go back to the deafult (non Compiz?) application switcher?

Note: I am using the proprietary ATI driver Ubuntu proposed me to install.