I was in a multiplayer server, and when I wrote something and entered it, the game closed on its own.

Put the summary of the bug you're having here

What I expected to happen was...:
What I expected to happen was my message would be posted into the chat bar

What actually happened was...:
What actually happened is it closed my minecraft window

Steps to Reproduce:
1. First, you type something, no "/", just a regular message
2. Then, when your done, hit enter
3. Finally, the game should close by itself... (This happened to me)