add: Sortable.options(oldParentNode).onChange(element); Sortable.options(dropon).onChange(element); 
context:   onEmptyHover: function(element, dropon) {    if(element.parentNode!=dropon) {      dropon.appendChild(element);    }  },
meta: 3991	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/3991/d29159eae8749c508d01bb447868321a3ba6bbfa/dragdrop.js/buggy/manager/media/script/scriptaculous/dragdrop.js