A bit of a newbie user of InDesign. I was using the programme this evening to set up some report templates when I noticed this strange obstructive grey box hovering near my essentials. It blocks my menus and I can't seem to click it. I tried clicking the thing it's pointing at (the essentials layout), but that doesn't turn it off. When I hide InDesign, it disappears, so I don't think it's caused by my OS.
What is it and how can I get rid of it?