this fixed my problem
$(function() {
$(".window").draggable({
helper: function (e,ui) {
return $(this).clone().appendTo('div#flowchart-demo').css('zIndex',5).show();
}
});
$("#flowchart-demo").droppable({
accept: '.window',
drop: function( event, ui ) { //on drop
ui.draggable.css({ // set absolute position of dropped object
top: ui.position.top, left: ui.position.left
}).appendTo('#flowchart-demo'); //append to container
});