On this issue, I originally did an upgrade from 9.04 and did not have that
problem. But my usual habit is to do a fresh installation a week or so after
release which I did yesterday. I experienced your problem. The button did
not work. I deleted it and re-added it and the new one worked. It looks
different as well. Instead of one button there are two, one for logging out
and one for shutting down.

I am glad your problem is straightened out.