If I duplicate to a stave below when in Page View, the music is copied to the hidden clarinet instrument which will (later) be used by the 1st tenor sax part. The clarinet stave suddenly appears in view. If I delete the music from it, the clarinet stave doesn’t disappear again.
I now cannot get the clarinet stave to disappear although I have emptied it of music.
If I add some notes to the clarinet at a later point in the score - after the bars which I had duplicated and then emptied, it finally goes away.