Pyxel window thinks it's always on top (Linux)
If I have a window overlapping the Pyxel editor as in this screenshot, then hold the mouse cursor in the indicated position, the music patterns can be heard. It applies when any part of any app window is overlapping, including the title bar.

I'm running MX Linux. Not sure if it's OS or Pyxel related but might be worth knowing about!

![SS-2023-07-29_19-40](https://github.com/kitao/pyxel/assets/3756822/f60f2e16-50d6-4736-8df5-3ec1440cd69f)



