something strange happens today:
I have setup a score with two Trumpets in C.
In Layout options I have setup under Vertical Spacing „Hide empty staves: After first system“
Now when I delete the music for the second trumpet at some place, the first trumpet gets an instrument change to Tpt in C. Very strange, also as the instrument is in C anyway. I can only avoid the instrument change label by inputting something into the second trumpet. This looks to me like a bug.