My Apple Pro Mouse recently quit working on my iMac G4. So I actually took advantage of my AppleCare, and called and ordered a replacement. I received the replacement on Monday, and AppleCare replaced it with the Apple Mouse that ships with the new iMacs, PowerMacs, etc. The original mouse that came with the computer was the "Pro" mouse. Is there a difference between the two? I know the Pro mouse has an adjustment ring around the optical sensor. What does that do anyways? Should I call AppleCare and tell them to send me the correct replacement?