Application switcher is broken

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http://askubuntu.com – After a normal update of my Ubuntu 12.04 install last week, my application switcher has stopped working. I've tried all different settings in CompizConfig, including a variety of shortcut keys and both switcher versions ("Application Switcher" and "Static Application Switcher"). So far there has been no way to get any form of application switcher to appear on my screen. Can anyone give me an idea what might be wrong, or where I might look for more information? Thanks for your help. (HowTos)