Seems like actions to insert, select, modify and delete MIDI notes under the mouse cursor are missing. How would you go 'clickless' editing in the MIDI editor?
insert/split note/cc at mouse cursor actions exist. you can combine move edit cursor to mouse with some other actions dependent on edit cursor pos and get pretty close...
found insert, unfortunately you have to first click in the editor to bring focus to the window. I added a button for delete notes to my toolbar, with that armed I can delete with a click but then cursor/playback position also changes.