Game window moves away from cursor

Minecraft window moves in an uncontrolled manner. When focused in Minecraft, then alt tabbing, trying to move the game window. 

To Reproduce:
0. Enable pause on lost focus with F3+P
1. Alt-tab away from Minecraft
2. Try to move the Minecraft window (by draging the top bar)
3. Note the movement of the game window, not intended by the user