I often import melody from some midi files exported from Musescore. When I try to change the instrument, say from piano to sax, the name changes but the sound doesn't. It seems that the midi files have patch changes embedded in them that do not get removed on import even though the Patch Changes box is unchecked. It seems the filtering isn't working.

I resolve this by importing the melody midi to BIAB, exporting it from BIAB to another midi file (say f2.mid) and then importing f2.mid to BIAB.

The same problem arises when I import some Musescore xml files - the melody instrument won't change.