Using '+' sign will not maintain ordering of list

[jeremychan]

If you use the + sign to add element from the available list, the order of the submitted fields will not be maintained. This commit will fix it.

[set-killer]

Thank you jeremychan,

This fix is a live saver :)
I don't know why this is not joined with the master.

btw: this also fixes the ordering of the elements on doubleClick event.