When working from automatic transcriptions it's often nessecary to change the layer of notes, to split upn chords into layers or to fuse layers into chords. A way to edit this with a keyboard short cut would be great.

MuseScore for example has cmd+alt+1-4 to assign selected notes to a layer (1 and 3 are @stem.dir="up", 2 and 4 "down") Since layers don't nessecarily have @n this will probably need to change. Maybe something like new layer, previous layer and next layer could be possible (@stem.dir would have to change to the majority of the layer). If you only choose one note from a chord, the chord just gets split. If their already exists another layer then <rest/> and <space/> get overridden. If the note position and length is the same between the changing note and the goal layer then they can create a chord otherwise it won't work.

MuseScore also allows to switch layers but that might not be needed since changing @stem.dir is easy with 'x' and changing layer order is also easy within the text editor.