I have a nested Sortable which is not working quite well on it's own, but I've added a Draggable too, which is causing even more problems.
- Sorting items between nested Sortables is almost impossible, try it ;)
- Dragging a Draggable into the inner Sortable also adds a new item to the outer Sortable as well
Example: JSFiddle
I guess this is just impossible to achieve with the current version of jQuery UI.
Edit: see comment below