Upgraded from Ubuntu 12.04 LTS to 12.10

[Csányi Pál]

Hi,

I just upgraded my Ubuntu Desktop and found a strange keyboard
behavior. 

I'm using Window Maker as a window manager.
I have installed keyboard-configuration and have a setup that worked
fine and works fine even now, but sometimes I can't to use keyboard or
mouse to switch to a next or previous Workspace. Then I just restart
Window Maker and everything works fine again.

What can cause this problem?

-- 
Regards from Pal