Ha, I was going to reply by pointing out some more things but guess what? Forget that. I just learned something that I've read about but never done. I had tried to write in a CmMaj7 and it wouldn't take it so what I did was right click in the chord box and check Chord Builder. In that window look in the upper left quadrant and in column 6 see the mMaj7. If you already have a C chord in the chord grid then the first column for Root already says C but if you didn't enter anything you would put the root in there first.

In the right hand quadrant there's a box that says Enter CmMaj7, hit that and voila there it is and it's spelled out CmMaj7 even though I tried to manually type it in just like that and it wouldn't take it. When I played it back the piano stayed right with that chord, no variations including when I used the substyle part markers. I also tried two other chord extensions and it was the same. The piano just stayed there, maybe that's the ticket but I won't know until I do some experimenting. Here's the screenshot:

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