I just got the 1.4.1 Pre-Release, and as I was playing in fullscreen, I wanted to switch back to windowed mode to check something. As soon as I toggled "fullscreen" off, MineCraft completely closed on me. No crash report/error screen. It just closed as if I had logged out. There have been other times in the past when MineCraft would just close like this, but I haven't had any problems like that in a while. Anyway, I'd appreciate it if this could be resolved as soon as possible. Bugs like these make the game less enjoyable for me, as with many other players, I'm sure.
1.4.1 Pre-Release Fullscreen "Crash" bug