If you maximize your screen while a world is loading there comes a border around your game. In addtion, if you click 'Save and Quit to Title' while there is a border around the game, sometimes Minecraft crashes.

What I expected to happen was that my game would maximize.

What actually happened was that my game stayed the same size but there came a border around the game.

Steps to Reproduce:
1. Open Minecraft
2. Click 'Singleplayer'
3. Load a world, but maximize the screen while the game is loading.
4. And there is the border around your game.
5. In addition, if you click 'Save and Quit to Title' while there's a border around your game, sometimes Minecraft crashes