I have been using Workspace switcher in Ubuntu just fine but recently have encountered this problem. The windows in the switcher don't fill the screen. I must have pressed some combination of buttons somehow but can't find any information anywhere in regards to resizing them.
As you can see in the screen shot it looks like a perspective view or something.
I should also add I have a dual monitor setup and nvidia graphics. The switcher still works but the fact the screens don't fit my actual screens is driving me nuts. Thanks in advance for any help.