A vocalist requested the key of E for a chart. That puts the trumpet in the key of F#. I thought it would be easier to read in Gb, so I transposed the part up a diminished 2nd. This is what it looks like now.
Is there a way to tell Dorico to change the double flats to something more readable?
You can respell chord symbols for instruments with a particular transposition.
But depending on what you started with and the context, you could also simply transpose the flow but without the chord symbols selected (if something isn’t selected when you transpose, it won’t be transposed) – so they’re not changed from their original chords. That may not make perfect sense for the new transposed key, but might result in simpler chords overall.
There’s also an option to prefer key signatures with the other type of accidental if that results in fewer accidentals, although I don’t think that would affect the result in this context as both keys have 6.