+1

Tangmo, there is a neat (free) tool by pipeline (member of this forum group) called "chord picker" if you have not discovered it already try it. It shows "in key" chords of selected. Recently pipeline introduced another feature of the app, to "hear" the chord when you click on them. Unfortunately it is done through "hot key" and not integrated. I can not think of a good reason why it (or similar) was not implemented into BIAB years ago.

Anyway, it is the best tool as of yet (or at least what I have seen) to hear and explore complex chords and input them into BIAB right from the app.

P.S. I know close to nothing in music theory, so the only way for me to make backing tracks for my songs is "by ear". Again, fully support your thoughts!

One more thing. One program helped me a lot with chords. It is by a talented German developer. It is called Sundog Song Studio.
I believe there is a demo available. Here is a screen shot: