Total side note, but hopefully it will help someone that runs across the same issue. I have one function that needs the draggable() method of jQuery UI (I'd be happy to do it with jQuery Tools, but they don't have functions for dragging)... Specifically my drag and drop thread movement system for mods/admins.
Long story short is I updated my end from jQuery UI 1.8, and something changed in jQuery UI 1.9.0 (and higher) that breaks jQuery Tool's tooltips (just by loading the jQuery UI script... not even doing anything with it). It turns out they have some functions in the same namespace as jQuery Tools.
So if you *do* need a load jQuery UI, you need to load it before xenforo.js (which is where jQuery Tools resides) so methods like tooltip functionality don't get overwritten by jQuery UI.