In my first experience with MuseScore 4 (after years with earlier versions) I was typing in a new score. Three pages in, the next note was to be tenuto D. Instead of hitting Shift-N, D I apparently hit Ctrl-N, D and wiped out all my work. That translates to New score, Don't save. I'm really bummed! I find myself wishing that New score (Ctrl-N) would start a new document while leaving the current, active one open (so editing two files at once, as it were).