Somehow my Setup/Layouts panel got out of order somehow, which affects the score dropdown in the center top middle (and elsewhere). I reordered it, but the No (Number) isn’t updating, as it did with an experiment on this on a different score. There’s also the sort layouts which I haven’t divined how that works. I don’t want to try something without knowing what will happen (thus forcing me to order them again) - how does this work? I have a bunch of parts in the Layouts panel but the “No” numbering does not match the list order in the panel.
Sort layouts: described here, sorts them according to type (full score/part/custom score) but not orchestral order.
Layout numbers: they don’t automatically update according to their position, you have to renumber them.