Just an FYI for those of you with a Microsoft Designer Bluetooth Mouse. I encountered a bug where clicking the buttons of the mouth would register on the computer it’s paired with, but moving the mouse didn’t translate into the cursor moving. There was also no blue light indicating the mouse was on / off or able to track.
Removing / unpairing the mouse and then pairing it again with the Surface Pro 3 also didn’t fix the problem.
Solution: Remove the battery from the mouse and then put it back in. Voila, fixed!