Nothing left to explore... except that big empty space over there.
I'm on the 4th floor of the CoC, and I tried to hit the auto-explore key. Only... I get the 'nothing left to explore' message. I had thought this was fixed.
I also thought I could upload screenshots. But, suffice it to say, I have more to explore on this floor when I got the message.
I have uncovered both staircases, at least.