I realize I was not clear. What I was trying to illustrate is that I am able to have instruments on my piano vocal score that are not on my full score. However, when I remove the rehearsal piano from the full score, it goes away entirely (including the piano vocal score). Any idea why that might be happening? I was trying to illustrate that issue but I can see how that might have been confusing.
Here, if you look at this file, You will see I was able to create the score and piano reduction part with instruments that are separated from the full score. Yet for some reason I cannot recreate this and I cannot remember how I did it.
The warning says you’re trying to remove a player from a flow. That’s a very different action than creating a layout with specific players.
Specifically, from the screen shot it shows you have selected a flow (from the lower zone). Select the layout in the right zone instead.