[Cancoillotte]

Actually, this method doesn't allow to add a staff in a middle of a multi-page pdf or am I missing something?

Moreover, it would spare a lot of time to many people having a button doing that for us, especially if you have to quickly write an alternate phrase, or add a missing bar during a rehearsal.
I agree it shouldn't be Mike's priority, but why not having it at the bottom of the todolist... ;-)