I make a world in superflat, with a layer of chests in it. it was really weird, first: chests doesn't render properly in the superflat GUI ( MC-12788 ) ok, this was alredy reported, but when the world was created, the chests were invisible, and minecraft was very laggy, especially when new chunks got generated. i messed arround with the chests, to see what minecraft do with they. sometimes chests appeared in places that doesn't have chests, and stuff like that. also, the GUI when i oppened some chest was very buggy. i make a "L" shaped triple chest, and it was looking like a double chest, with one of the chests invisible. i exit the world and reenter it, to see if minecraft render the chest in a different way, and minecraft normaly entered the loading screen, but, insted of opening the world before, it just opened the main screen, i entered the world again, and again the main screen. some seconds later, minecraft just crashed, and, when i entered the crash-reports folder, there was TWO crash reports with a -server on the name. Sorry, i'm from Brazil and my english is not perfect.