Cannot Remove MS Bluetooth Mouse from XPS13

Hi vinniec,

I would suggest you to follow the below steps to remove Bluetooth added devices on the system.

1. Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
   (If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, click Settings, and then click Change PC settings.)
2. Tap or click PC and devices.
3. If you're removing a wired or network device, tap or click Devices. If you're removing a Bluetooth enabled device, tap or click Bluetooth.
4. Tap or click the device you want to remove, and then tap or click Remove device or Remove.

I have the same problem.  Dell XPS 13 and Dell WM615 BT Mouse.  Unable to unpair.  Unable to remove.  Tried many different options to remove stubborn device from computer.  Reappears all the time upon restart.  Bluetooth settings say mouse is paired, but, not connected.  It worked for a little bit when I first got mouse, then became more erratic with each booth cycle to the point it stopped working.  Interestingly it works just find with my other XPS 13 without any problems, so it's not the mouse hardware.  Other blue tooth devices work just fine on this computer (like my wireless headset) so I'm pretty sure it's not the blue tooth transmitter/receiver.  I have tried every combination of solutions that I can find on the internet and some unorthodox ones as well.  This annoying as all get out.