Play Panel and Mixer cannot be brought into visible space.
I usually run Muse score on a laptop which has a 2nd screen attached to it. I have the main program on the left (main) screen and any dialogs like play panel and mixer on the right.
When I run Muse score when I'm not at home, i.e. my 2nd screen isn't available, I cannot get the play panel or mixer to show. Presumably they are there but off-screen and I cannot find a way to move them to the visible area of the screen.