From searching the forum posts I get the feeling this might just be the way Dorico is set up.
My issue is that I have a Segno and a rehearsal mark in the same position. It all looks fine in Page mode but I write in Galley Mode and just spent 30 minutes trying find a Segno which I wanted to remove. Finally found it under the Rehearsal Mark!
I would find it useful if the Segno could sit above a coincident Rehearsal Mark in Galley Mode. Is this possible? If I try and drag the objects the Rehearsal Mark jumps to the next bar line and the Segno jumps erratically.
Can this be set up so they are both visible by default in Galley mode?