Okay, what the heck is this? I've only encountered this problem once before the update was out and now I get it every single time I start a server, single-player or public.

My obscenely low FPS is caused by this problem and I'm sure of it because it never happened before(by before, I mean when I played in single-player servers to test the enviornmental stuff).
Notice how the paint, box, and item slots are out? I set them to hide in the options. Obviously, they didn't.
Also, when I type something in the chat without pressing enter, the text ends up near the center of the screen. And when I press enter after typing it, the chat message doesn't appear!
That's all I can find, and if there's actually more, oh god...