Fullscreen bug.

I play Minecraft always in maximal format (see Screenshot 1) but when i click on Fullscreen "On" and "Off" (see Screenshot 2) I can't resize the windows anymore (see Screenshot 3). The only thing I can do is restart Minecraft.

Steps to Reproduce:
1. "Fullscreen" modus in "Video Settings" in Minecraft is "Off".
2. I set the Fullscreen on "On" and then again on "Off".
3. Now I can't play the Minecraft windows in maximized anymore, until I restart the game.

This bug is in all Minecraft versions though, not only in Minecraft 1.9 Snapshots.