perdido:

- I pulled up Johnson's Rag (I don't have Peacock Rag) and the FOLKRAG.sty
and tried a few different keys. It seems to work fine here.
Is there any chance that your file has "frozen" tracks, so they won't change key?

- Check the last couple of bars (where it starts to fade) to see if there's a "red" mark in any bar. It could be that someone set it to start a fade at that bar. (you can use F5 to check the bar settings).

- When you click the "Notation" button, then the "Opt." button, at the very top in the center there's a box for
"Bars/Screen". Is that set to 2 or 4?

If you want to post your BIAB file, someone wiser than I can probably sort it out for you.
Let us know what version and build number you're using (Found under Help > About Band In A Box).

Good luck!
LLOYD S