With bootstrap panels, the placeholder of jQuery UI sortable is always at the left side

With bootstrap panels, the placeholder of jQuery UI sortable is always at the left side

I'm trying to implement sortable bootstrap panels with jQuery UI.

But the placeholders keep stay at the left side when dragging the bootstrap panels.

Please see my code in http://codepen.io/anon/pen/oXrVVq


Thanks.


[Edit:]

I think the placeholde is to indicate the new position of the moving element.

Please see below demo.