ColorCalibrator tool stuck on cursor when clicking out of the Editor

Using the ColorCalibrator tool as a cursor by holding "\" gets stuck if you click out of the Editor while hold down the key. 

1. Ensure that the viewport is the active window in the Editor
2. Press and hold "\" to bring up the ColorCalibrator tool as your cursor
3. While still holding "\" click off of the Editor window were it no longer becomes the active window 
4. Now let go of "\" and click back into the Editor

Result: The cursor is now stuck as the ColorCalibrator 

Expected: The key is no longer held down so the ColorCalibrator should not appear.