Mystery Window Exposé...d
Hello,
Using mission control to show all open windows, a mystery window slides out from the side of the desktop. It says "Devices" in the upper left corner and also says "Select camera or Scanner" across the title bar at the top. I can't select it, nor close it, nor find out from where it came. I've quit all programs, Restarted, Relaunched Finder and looked at the Force Quit window for any stray programs that might still be open. Nada. Any clue as to what is going on?
iMac 5k, late 2015, High Sierra, 10.13.3
iMac with Retina 5K display, iOS 10.3.3