separate button or input for midi keyboard and controller
It would be nice to have a separate button to enable/disable midi input for the note input device (midi keyboard) and a midi controller for play control (start/stop ea)
I use a midi keyboard for note input, and have a 4-button usb midi foot controller and sometimes a midi korg midikontrol to control playback for MS. Currently the midi streams are merged in the jack midi backend to a single stream to the MS midi input.
When you switch off midi input in MS, then not only note input from my piano keyboard is blocked, but also the play control messages from my midi controllers, making them useless.
Having a separate button for controller messages, or have the current button operate only on note input messages, will solve this problem.
You definitely will wnat to easily enable/disable note input messages, not all (currently selected) staves will produce a nice sound when you play the piano along MS.
In MS4 (linux version), playing along MS playback sound horrible with a delay of about 02. to 0.3 sec.
N.b. there are a lot of keyboard instruments that have built-in buttons for play control, that you will want to use to control MS; a separate midi input port in MS might not be the solution in this situation.