BIAB for mac 2020 here. I want to change the instrument assigned to the Melody track to a new patch at the beginning of a bar. Like let's say I want to change from Music Box (MIDI patch #11) to Violin (patch #41). It looks like I should be able to do that through the Bar Settings dialog, by going to the bar where I want the change to happen, opening Bar Settings, putting '41" in the box under "Patch" and opposite "Melody", and hitting OK. At least that's what I get from the manual (p. 154).

Thing is, the instrument doesn't change when I do that, as far as I can tell. I can mute and change volume and those work properly, and if I change the patch number I see the red squiggle under the bar number, but the instrument still sounds like a music box. What am I missing? I'm using the _WHIMSY style as a basis, if that makes a difference.

And in a related question, can I add a second Melody track to a song, and if so, how? This seems like it'd be pretty basic for things like violin-clarinet duets, but so far it's eluding me.