Thanks for yopurs answers.

I answer a little late, taking an example to illustrate how ergonomics are not always very intuitive.

Lately I'm trying to assign midi drums to a drum track that had real drums.

I tried directly to assign a midi drum to the drum track (standard drum kit), but the instrument change was not made, without any error or warning message.

I tried different settings or actions, like "return track to style instrument". Without success.

I finally found the action "Force Drums track to midi drums" and it fell into place.

But admit that this is not very intuitive ...

For me, actions like "Revert track to style Instrument", "Force drum track to midi drums", should not appear in the user interface and should be implied when selecting another type of instrument.

Instead, if you don't do it explicitly, the instrument change doesn't work without knowing why.
And we fumble around for a while before we find the right option.

From my point of view (that of a user who wants an intuitive approach, without having to guess the logic of the developers), it is not necessary to explicitly ask that we will change the instrument. It should just be enough to change instruments!

So ergonomics is not BIAB's strong point (but there are others!)