Strange Key Signature doesn't work right
I'm writing down a tune that seems to notate best using an (unusual) key signature which uses both sharps and flats. I started the notation in G and then noticed that all of the B's in the score are flat; so I created the key signature that you see in the attachment, with both an F# and a Bb, and then moved it into the score. The key signature appears as it should at the left of each staff, but the Bb notes in the score retain their flat signs, and removing the flat signs on these notes seems to make them natural despite the flat in the key signature (judging by the MIDI playback.)
Is this a bug, or do I just not understand?
Thanks - jon