I noticed a problem in ui.droppable.js @ line 137. In the event that the drop target has the attribute of overlow: visible, the existing stored values are _NOT_ valid, but are assumed to be so. When this scenario occurs, you cannot do a drag & drop reorder of sub-content past the original dimensions boundaries. For my needs, I needed to deal with Vertical overflow (as most will), and made alterations as follows.

The simple fix is this:

--- t = droppable.offset.top, b = t + droppable.item.proportions.height;

+++ t = droppable.offset.top, b = t + $(droppable.item.element).outerHeight();