Inspector in upper left corner of screen won't move or disappear

When I was working on a tune today, I opened the inspector, and it appeared in the extreme upper left corner of the screen, with the top part of the inspector (including the little x in the left corner that would allow me to close the inspector) out of view. I could not drag it to another location or close it, and it covered several parts of the screen that I needed to access to continue working, such as file and play. I somehow got the inspector to go blank, but a gray square remains in the corner. I tried to resize the main window, and now it seems to have disappeared behind the gray square. I tried closing the program and restarting the computer, but when MuseScore opens, I only see the gray box. How can I move or close the inspector? (I think the problem is compounded by the fact that I set MuseScore to resume where I left off when I reopen it. If I could get it to start fresh, probably that would fix it.) You can see the gray box in the attached screen shot.