When I press Win+W expo only shows the windows of the current workspace. I remember 12.04 had a similar problem (it was a Compiz bug) and there was a PPA to solve that (see this question). The problem is that PPA does not seem to be maintained any more for Quantal 12.10 at least.
I really don't know if this is related to that bug or is just some configuration problem...
So how can I change this behaviour and get expo to show windows from all workspaces?
2 Answers
This is not a bug, but a configuration issue. You need to install Compizconfig-settings-manager from the Software Center, and then, when you run it, go to the scale plugin.
From here, you have to set the option "Initiate Window Picker For All Windows" to use Super+w. This will complain of a conflict, but all you have to do is disable "Initiate Window Picker".
You can begin using it immediately.
As of 14.04, you could expo windows from all workspaces using
Shift+Win+W
