Presently, notes in the MIDI Editor are assigned by Pro Tools. This is inefficient and difficult to follow (if for instance you're doing a big orchestral session with a lot of different parts that you want to view/edit simultaneously). A better solution would be allow the choice of setting colors for the notes/tracks in the MIDI Editor to either be user-selected from a palette, or to follow the main Track Color.
For me, it's really become a problem, because the light green color that is assigned to the "first" MIDI track is very hard to see against the light background of the MIDI Editor window. So, I'm always struggling to edit my top line in a section.