I see this as, highlight the measure or measures, right-click, and have Regenerate highlighted selection as a menu choice.
1, 2, 3 done.
Do it until you hear what you want. Provide an Undo that works as many times as you have set the Undo level.
So the context menu could say:
● Regenerate highlighted selection [then select track, or all tracks]
● Undo regeneration
● Cancel
To Soundsmith, the OP, would this meet your needs?
Yes!!
And the UNDOs are very important, to correct mistakes and things that didn't go the way you expected.
I already wish there was at least a single UNDO for being able to go back to the previously generated version of the song if BIAB automatically regenerated something before you were ready and had forgotten to freeze something.