Focus problems with Compiz Expo and focus-follows-mouse

I use the Expo plugin from compiz-config-settings-manager to switch between desktops (normally by mousing into the top-right corner, but this same bug happens when I activate by keyboard shortcut).

On 11.04 this worked perfectly, but on 11.10 I'm finding that focus gets left on the previous desktop. Frequently (perhaps always?) with maximized windows, I find keypresses going to the window on the previous desktop. I can restore correct focus by mousing out of the window into the titlebar and back.

My guess is that the focus is decided based on the window exit/enter events, and that compiz has stopped sending them in this case. If that's so, the fix may be fairly simple.

I have some programming experience, if pointed in the right direction, it's possible I can fix this myself (it is _very_ annoying).

I'm otherwise happy with the unity focus-follows-mouse experience (I rarely use the application menus, usually my windows are maximized anyway, and if not it's easy just to use a keyboard shortcut).