[Steinway]

The Composers -> Edit screen that you mention (which was messed up in your case) seems fine here. I have only seen this problem where I described, in the Edit song -> Select composer dropdown. It was fine for a while yesterday, but tonight it's messed up again.
I have "Šulek, Stjepan", and use the Norwegian translation. But I seem to remember seeing the problem even before the Norwegian version was released (i.e. when I was using the English version).