Further to the earlier discussion on markings for instrument changes, I have a couple of suggestions that may or may not be useful.
Allow setting a different label for the instrument to be used in the instrument change annotation. This could be done by extending the dialog for instrument name (in the setup mode) to allow defining an additional label for this case. Then one could label (for instrument changes) a staff as “tutti”, and another as “solo”. It makes no sense to use these labels as staff labels in the score, but would fit the bill for moving between solo and tutti in a part.
Allow it to be turned off altogether
Allow it to be positioned and styled.
There may need to be rules around when it appears. It’s one thing to move from Bb clarinet to A clarinet, where it’s the same player, it’s another when there are occasional solo bars in a sectional part which require another stave.
Cheers and keep up the great work.