Minecraft Crashed When loading A World And The Launcher Lacks

Put the summary of the bug you're having here

What I expected to happen was...:
To load a SuperFlat world

What actually happened was...:
I clicked on play world
Minecraft: (Not Responding)
then it crashed

Steps to Reproduce:
1. Launch Minecraft
2. Click On SinglePlayer then Create New World
3. Gamemode: Creative, More World Options, World Type: Superflat.
4. Create New World