I'm using 11.10, and when I use the Expo feature and then return to a active workspace, any open windows are click-able, but they don't actually change.
Here's what I mean:
In Google chrome, after Expo, I can click on links/new tab button, etc.
However, though the mouse will spin and the program is actually working, the program won't update visibly unless I minimise/restore (or vice-versa) the entire window.
Edit: I've found others who have the same problem (unrelated to Expo). It would seem that though the program remains running, its content won't refresh unless it is first maximized then minimized.
Edit: Problem solved by resetting compiz.