Fix bug concerning sort and drag

Steps to reproduce bug (tested with Firefox 12, IE 7, and IE 8):

1. Drag an item within selected list to change sort order.
2. Drag a new item from available list to selected list.
3. Check order of select element values.

I created a [jsFiddle demo of the bug](http://jsfiddle.net/toxalot/nPte2/). If you follow the steps above, you should notice that the select element values are not in the same order as the displayed items. If you inspect the optionLink data, you should notice that the option linked to the dragged item is also linked to previously sorted items.

I created another [jsFiddle with the proposed fix](http://jsfiddle.net/toxalot/QddP5/).

This is my first time using any VCS and first time contributing to open source. Please let me know if there is anything I should do differently.