I'm using an M1 MacBook Air running Big Sur, with Vienna 3.7.0. Sometime yesterday, the Vienna app appeared on my screen, centered left-to-right, near but not at the top. I cannot get rid of this icon nor select it, nor move it. Quitting the app does not affect it. Only by restarting did I get rid of it. This icon is in the foremost layer, so it covers anything else on the screen. Judging by its position, I think it may be left there from when I launched the app using Launchpad.
I don't know what to do about it, but I think it needs to be reported. It may even be a Big Sur bug - I can't tell - but it is certainly annoying.
Tom Bajzek