I ordered a Magic Mouse last week, and I'm pretty happy with it..... but, I was wondering if it's supposed to have an area on it that isn't touch sensitive. On my Magic Mouse, the area that I have colored in red isn't touch sensitive. When I swipe, nothing happens. I use BetterTouch Tools, but I've only created a couple of gestures so far (for example, one of them is swiping on the Apple shows me the desktop). Is this part of the design (is it a place to rest your wrist?), or do I have a defective unit?