Could you tell me what files were updated to make this work? I'm using a pre-GU57 custom UI (old blue windows, no SC icon on merchant and such) and I think I'm missing some files as I didn't really saw anything new. Not that I searched mind you, I wasn't expecting a patch with something new and didn't check the patch notes.
Problem that could be related: I was trying to sell a bunch of fuel from all tiers on the tailor NPC upstairs from the South Qeynos bank and broker. I sorted by price, as I often do, and the fuels started jumping around in my window randomly, switching order while I was clicking and I ended up having to buy back several items that I didn't want to sell but clicked on without intending it. Sorting by name fixed the problem and it's the only time it did it.