HorizontalPanel hp = new HorizontalPanel();
hp.setWidth("100%");
final Label draggable = new Label("DRAG ME");
final Label droppable = new Label("DROP HERE");
DragAndDropContext d = new DragAndDropContext();
d.makeDraggable(draggable, true);
d.makeDroppable(droppable);
// d.addDropListener(droppable, new DropListener(){
// public boolean onDrop(Widget dropped) {
// RootPanel.get().add(dropped);
// droppable.getElement().getStyle().setBackgroundColor("white");