Key change on instrument change with default key

Hi Dorico team,

when changing instruments, e.g. from Horn E flat to Horn F, I noticed that the default key only gets transposed when explicitly set. Example (transposed view):

Some bars with no key set (default Horn E flat):

After instrument change to Horn F:

Same bars with key explicitly set (Eb):

After instrument change to Horn F:

I would have expected the last result (automatic key change) even with no explicit key set. Does that make sense?

I wonder if this has anything to do with the kind of horn chosen, which can be with or without key signature.

I chose the horn with key signature (“Horn E flat”) - that is why I was expecting the signature to be implicitly set.

I think there is a small misunderstanding: the “default key”, as you call it, is not C major. It is “no key”. So when changing to another instrument with a different transposition, the new key still is “no key”, and the accidentals will be added where needed according to the new transposition.

If you want C major (or a minor), you have to set it.