Try not to get distracted by my amazing Paint skills.
So for those who don't know what I'm talking about, this would be a list of, well, stuff. Not necessarily a list of options -- I was planning to use it to list achievements a player won after beating the level. Anyway, you could click inside the box and scroll through the list (is it possible to make it scroll using the middle mouse wheel, by the way?).
I planned out how to do most of it, but the thing that stumps me is that the options that don't fit within that inner box have to be hidden somehow, as if the inner box is a window into another layer. I'm not really sure how to get that working. Any ideas?