I have a fresh install of ubuntu 12.04 and noticed alt-tab wasn't working. I followed some advice and installed compizconfig settings manager, wherein I checked Application Switcher. Then alt-tab worked, but sometimes (lately, every time) it crashes the desktop. I'm using gnome classic (which by the way I have not been able to set as the default... I have to select it every time).

After hitting alt-tab, the screen freezes, and the mouse can be moved only briefly every few seconds, and clicking anywhere doesn't seem to do anything. Some parts of the screen become a bit distorted. One time it recovered, but then crashed again as soon as I clicked on the time in the upper-right corner.

Any idea how to fix this? Where can I look in the log files? Perhaps I can uninstall compizconfig (after all, it does come with a warning that it can wreck your system) but then how can I get alt-tab to work?

Many Thanks.

EDIT: I guess not many people have had this issue. I suspect it's a problem with my graphics card - perhaps it doesn't like the fancy effect involved with alt-tab window-switching. So a revision to my question would be: how do I enable alt-tab to switch windows for me in the simplest, safest, non-fancy way? Can I do it without compizconfig?