jQuery odd behavior of collapsible/movable panels with drag/drop within them

First of all, huge kudos to 'Web Developer Plus' for writing most of the initial code!

I have a list of 'items' which I can drag into any one of the blue boxes inside the widgets, and then sort them. This works fine. It's only when I start toggling these widgets (showing/hiding), or moving their positions, that things start going weird.

Example 1

An item (or items) can be dragged into (and sorted) ok. If I then move Widget 2 above Widget 1 I can't drag anything into Widget 2. I don't get any errors in Firebug. Just nothing happens.

Example 2

If I 'hide' the contents of Widget 2, I cannot drag anything into Widget 3, 4 etc (Widget 1 is ok). If I then 'show' Widget 2 again, I can drag into Widget 3, etc but not Widget 2...

My code is here for you to play with: http://jsfiddle.net/gD94w/4/

Any ideas? Posted another开发者_JAVA技巧 topic regarding this, but hopefully I've worded this better & I might get some help(!). Cheers folks :)