Mixer panel not always dockable/floatable, depending sometimes full screen enabled or not.
Since this commit: https://github.com/musescore/MuseScore/pull/4526/files, the mixer panel can be dockable and floatable. Really good improvment and for the consistence with other panels behaviour. Thanks for this.
With the sames nightlies (eg 7271e04), it works fine with my desktop computer under Windows7.
But, despite many attempts, I am really completely unable to succeed with my laptop under Windows10. It doesn't just work. The blue area is not created by going to the edge of the screen (double-click not works too). In short, it's a failure, and I don't understand why.
Could this feature be dependent on a version of Windows? (7 vs. 10). Hard to believe? Or, the size of the screen?
Or something else?