Is the track frozen?
Is it a true MIDI track (yellow) or a MIDI Super Track (pale blue)?
Even if the track is frozen I can still hear the changes I make in the Piano Roll View.
I froze the track then made my changes. In another test I made the changes then froze the track. In both cases I heard my MIDI changes. I tried with both super MIDI tracks and regular MIDI track. I was using the play button.
I can get the identical results as he does IF I hit the regenerate play button.