Brackets: disappearing, refusing to stretch

I’m facing frustrations with bracketing my score. It didn’t bracket the Glockenspiel with the rest of the percussion, even after I grouped them in Setup Mode. As such, I tried to manually bracket them in Engrave Mode. This deleted all other brackets. When I put in all the other brackets, Dorico refuses to add Horns 1 and 2 to the brass grouping (even though it does this automatically when brackets are set to default). If I stretch it over the horns it just springs back of its own accord.

As it is, I’m faced with the choice of either an incorrectly bracketed glockenspiel or an incorrectly bracketed horn section! I would massively appreciate any help with this issue.
LSO Piece – draft (1.18 MB)

IIRC Dorico does not bracket pitched percussion with unpitched percussion instruments by default.

Hi Derrek, thank for responding.

That’s not the problem, right now, however: I can correct the pitched percussion bracketing manually, but when I do that it breaks the horn bracketing. I then can’t manually fix the horn bracketing! So I’m currently looking for a solution that manually fixes the horns. (Though any other work around would be great too!)

Unfortunately I can’t see any way around this at the moment. The problem is that the bracket and barline changes work on the identity of the staff at the top and bottom of each grouping. The fact that the glockenspiel is one of several instruments held by the first percussionist is what’s tripping things up, because the identity of that staff is then changing. Ideally I think we should have an option in Engraving Options to make it possible to say that Dorico should bracket pitched with unpitched percussion, perhaps with the additional condition that the instruments must be held by the same player.