jQuery UI sortable scroll helper element offset Firefox issue-Collection of common programming errors

I managed to figure out a fix for this:

$( "items" ).sortable({
start: function (event, ui) {
 if( ui.helper !== undefined )
  ui.helper.css('position','absolute').css('margin-top', $(window).scrollTop() );
},
beforeStop: function (event, ui) {
 if( ui.offset !== undefined )
  ui.helper.css('margin-top', 0);
},
placeholder: 'placeholder-class'
});

Basically, you need to listen for the sortable’s “start” event to add the browser’s current scrollTop() value to the helper’s position, and then you need to listen for the sortable’s “beforeStop” event, to remove that offset before the item is officially placed back into the list at its new position.

Hope that’s helpful to someone!