Problem with upload dialogue box

For some reason, in a Sharepoint site I inherited, every document library has the same upload dialogue box.  Normally, the upload box shows only the fields you have in the library; that is, if you have a doc library with columsn for name, title, and date, then that's what you see when you upload to it...and every library has an upload box that matches THAT library.

Well, in this site, there's one upload box for all libraries, and it has a ton of fields in it.  I figured out how to hide the ones I don't want in my most importat library, but really would like to get the thing back to operating the way it's supposed to.  Any ideas about what's causing this?  I suspect it has something to do with content typing, but am not 100% sure.