Mistake in transposing instrument key signature
I'm using a score downloaded from MuseScore.
It's in Bb maj. So the B clarinet part should be transposed C maj. The notes are right, but the Key Signature is coming out as D maj. on the Score
I can't find a way to correct this. I've tried to isolate this stave; I've tried to change instrument and then change back to clarinet; I've checked that the transposition in the part properties is right (a major2nd).
It doesn't seem to be a general MuseScore problem as I've set up other scores which transpose correctly.