Today while my daughter was playing Minecraft I noticed that there appeared to be a translucent gray bar covering most of the screen - everything except a margin at the top and bottom. It went away any time I went into the menus, and after fiddling around with the settings I couldn't get it to get away. I tried joining a second player and the bar got narrower, still covering the entire width of the screen but extending only a bit above the inventory bar to just past 1/3 of the screen up.
How can I get this bar to go away?
Update: I realized this bar looks like the gray bar that pops up whenever there is text - except taller. So I started spawning creepers until I couldn't any more, and sure enough, I did not get any messages telling me I was at the limit of how many I could spawn, even though I could no longer spawn more.
Update 2: I was able to make the problem go away as described in the answer below, but after restarting a second time, I am now stuck with the rotating progress "boxes" at the main menu; it has been sitting there for over ten minutes now not letting me do anything (except turn off the unit, which doesn't fix the problem, as soon as I try to start Minecraft again it gets stuck when I try to log in.)