How do I get my browser minimize/maximize boxes back?

This morning I turned on my PC, and after booting up, I noticed a major change in my Firefox and IE browsers. I didn't change any settings, but my browsers' windows are larger than before, so much so that the minimize/maximize boxes in the far upper right of the browser windows are missing. There's no way for me to hit the red "X" or to minimize a window. The area where they normally would be is all black, as if there's a small, black border at the top of the window.

BTW, when I searched about this, I went to try and reset my default theme in FF, especially; however, I was already using my default theme.

Edited to add: Now the URL window and everything along the top is gone. It's stuck in Full Screen mode for some odd reason, and I didn't even change anything. Argh!

Any idea what caused this and how to get them back?