Thought I was losing my mind and this was never actually a feature, but then I tried it in Chrome and it worked fine. x__x
When using Firefox and trying to organize the items in a pet's treasure, the items won't move. You just end up dragging a semi-transparent image around like a fool. Do Subeta and FF not get along or something? o3o Or is the issue on my end? I've noticed shop search no longer offers suggestions (when using FF), either, but chalked that up to the site lag from the event.
It's working fine for me in Firefox.
I'd try clearing cache and cookies. See if that helps.