There was some kind of bug with re-ordering in the root playlist, something that would cause emplode to crash, I don't remember what it was exactly, and so one of the ordering methods got disabled in the root playlist.
I wrote that code, so I figure I can be definitive here.
The problem is that the root playlist also has the "Unattached Items" playlist (FID 0x110) in it. It's always there; it's just that emplode hides it from view. I think we hid it around the time we were working on the Rio Central (because it has soup, and doesn't need everything to be attached).
Then, shortly before leaving for the pub one evening, someone discovered that reordering items by dragging them crashed, but only in the root playlist, and specifically because of the hidden entry. I was thirsty, so I simply disabled drag-and-drop reordering in the root playlist.
A proper fix actually turned out to be harder than you'd think, so we never got around to fixing/reenabling that feature.