rniemeyer/knockout-sortable — pull request #7 by MatveiFisenko (2012-02-29 10:01:49+00:00)
Title: Adding 4th parameter to afterMove callback. 

Use it in case when we have 1 sortable array and 2 buckets sharing it.

The simplest case is when "high priority" and "normal priority" buckets from your example http://jsfiddle.net/rniemeyer/Jr2rE/ share one array.
We need to know if item moved from one bucket to another, or it just changed place in the same bucket.

We can achieve it by calling " if (this !== elParentNode) " in afterMove callback.