I'm on 10.6.2 and got notified of a few software updates today including the superdrive firmware fix. Ran the updates and rebooted and then did the superdrive firmware and rebooted. I have an MS sidewinder mouse that has five mouse buttons all recognized by OS X. For the past year I have used mouse button 4 to launch expose and mouse button 5 to launch spaces. After these updates Spaces will no longer launch when mapped to any button on the mouse. I've verified that the same button (button 5) works to launch other things such as Expose. Can anyone else confirm this and is there any kind of fix or workaround to the issue?