Once i upgraded to Tiger, i had to reconfigure my mouse naturally. I set the desktop expose, by which i mean hides everythign, thing set to mouse button 3. I then had to reinstall the drivers for my MX 510 mouse. I set one of the buttons as button 3, but it does not do the desktope expose thing. I then change the settings of the button to be number 4 which is the regular expose, and it works. So i know that the button is working but for some reason or other it does not want to do desktop expose thing. Sadness.....