Good descriptions, thanks!

FWIW, this is where I think an improvement could be made -

If you import a MIDI melody onto a track (e.g. the Melody track, or any of the Utility tracks) the interface that lets the user change that track from a MIDI track to a RealTrack is unchanged, despite the fact (I now know!) that a RealTrack cannot play the MIDI melody, and selecting a RealTrack instrument (rather than a MIDI or HI-Q instrument) will destroy the melody note information you have imported.

Nothing is greyed out, and there are no warnings - just a silent destruction of what you've imported. (IMHO, that should never happen!)

You can indeed prevent such destruction by Freezing the track after importing the MIDI, which is good, however, again, if you go thru the UI to select a RealTrack instrument your selection just silently does nothing (on account of the freeze) instead of raising an informational message such as "RealTrack instruments are not a valid selection for tracks containing MIDI data." or "Instrument changes are not permitted on a Frozen track".

BIAB for Windows 2023 (1006)