I haven't totally flushed this out yet, but one thing I do notice with the new Beta, is that the scrolling function of the Magic Mouse doesn't seem to work. On previous versions, I used to scrolling function of the mouse to zoom in and out (which still works on those versions), but it's doesn't seem to work on the latest Beta. I've played with some settings, without any luck. The Magic Mouse is an odd, quasi-multi touch device, so I'm not sure if that plays into things or not. I'll keep using it and see if I notice anything else.