One of our instructors, Nick Marchant, has this bug. I can't reproduce this bug at all. So I had Nick test it, and made all sorts of changes to try to isolate what the problem is.
I think the problem has something to do with the file list. We now have over 200 jam files, and the list just doesn't seem to load correctly with certain firefox installs.
I would be curious if Ron F did anything unusual to his Firefox install before the problem fixed itself.