Magic Mouse only tracks diagonally
Magic Mouse suddenly started to do this. It tracks OK, a little sutterty perhaps, but it only tracks on a steep diagonal on a lower left/upper right axis. I see it's been reported before but never saw a solution. If any one knows how to fix this, any help or suggestions would be much appreciated.
The Bluetooth connection seems good, and the batteries are strong. I've rebooted and zapped SMC.
Thanks.
MacBook Pro with Retina display, OS X Yosemite (10.10.3), Mid 2012 2.6G i7