Fullscreen mode looks movement keys

Pressing f11 while running casues a num-lock-like effect.

What I expected to happen was...:
I had the game out-of-full-screen mode, so I tried to put it in full-screen mode while running forward.

What actually happened was...:
After that, I let go of W (The run button.) and kept running..

Steps to Reproduce:
1. Simply run forward.
2. Open up full-screen mode.
3. Release forward.