+1 Really need this when recording divisi strings and want to edit the modulation for all of them at the same time. Right now I have to delete all but one midipart that has the same data, and then alt+shift and drag them back to to where they where. That will copy the midipart and then I can select only one part to edit midi ccs and all the other tracks will follow.
There is a command to “convert to real copy” that I can use to make the parts independent again after editing. But why isn´t there a command to convert the midi parts to shared copies? if they are all exactly the same, that should be no problem. That would make it so much faster!