I was working away & minimised AutoCAD Architecture (ACA) to do something in another application. When time came to restore ACA it appeared the main application window had disappeared. It was still active on the taskbar but didn’t restore when selected. Then I noticed clicking the taskbar icon made the “A” App button appear (as seen below) on the second monitor where I park the Properties & Project Navigator Palettes, which were both still functional.
Closing the Properties Palette revealed a scrunched up fully functional main window small enough to be totally hidden apart from that peekaboo App button! I guess it was OS resources or something in the app/graphic driver/card/monitor chain misbehaving because I didn’t put it there!*
Dragging the window back to the main screen & resizing it restored normal operation until I’d saved the work in progress and completed a precautionary restart. Perhaps ACA felt like playing games?
* Unless there is a “Hide application behind Properties Palette” variable or keyboard shortcut that I don’t know about!