I am using YUI's Drag and Drop utility to add some drag & drop functionality to a CMS I'm building.

This works just fine and is very easy to set up, but the thing I'm wondering about, how do I restrict the dragging? In other words; how can I make sure an element gets dragged within the borders of, say, some div and not outside them?

I have looked through the manual, but couldn't find it. Some pointers would be great.