> Why can't we hear all the MIDI tracks from MSG itself?  It seems we
> can only hear one MIDI track at a time - right?

you can - from the editor module, with one trick or another. you'll have
to assign a different midi channel for every track  and set up a 'multi mode'
on your synth with the according channels.

assigning different channels in msg works as follows:
1. create some tracks
2. go to 'select events'
3. set under 'layer' (track) both values to '1'
4. click 'new'. now you selected all events of layer 1.
5. go to the 'modify' module.
6. click on 'channel' to enable modify
7. choose function 'set' and value 2.
8. click modify.
9. return to editor and play it.

i could add general midi feature so as to select a channel and a program number
for each layer - but remember, the play routine is not designed to replay
multiple lines.

hellmuth