Sortable in Sortable?

Sortable in Sortable?

Heyho,

I'm trying to create a sortable container into another one, basicly it works well.
But when i start to drag Elements from the inner sortable to the outer one it starts to flicker.

http://jsfiddle.net/x34WN/

The background of this is:
I want to create "Portlets" on the site that are sortable, but the content of the Portlets should be also sortable.

If someone got an Idea, im open for anything :>

Thanks in advance.