drop widget beyond the AbsolutePanel gwt dnd - gwt

Question

I'm trying to drop my draggable widgets out of the boundary panel (AbsolutePanel). In my case draggable widgets is an image. And I want to drop it, so that there will be visible only a part of the image, but when I drop it, and some parts of image beyond absolute panel, it drop automatically within absolute panel.
I tried :
dragController.setBehaviorConstrainedToBoundaryPanel(false);
and thought it means that I can drop it where ever I want, but it doesn't work.

Answer 1

And the working solution :)
Here is my code:
public class myEntripointClass implement EntryPOint{
AbsolutePanel droper;
public void onModuleLoad() {
Panel main = new AbsolutePanel();
droper = new AbsolutePanel();
droper.setHeight("300px");
droper.setWidth("500px");
main.add(droper);
content=new AbsolutePanel();
bt = new Button("Drag and drop it");
content.add(bt);
lb = new Label("Label drag and drop");
content.add(lb);
main.add(content);
manageDnD();
RootPanel.get().add(main);
}
private void manageDnD() {
PickupDragController dragController = new PickupDragController(
(AbsolutePanel) content, true);
dragController.makeDraggable(bt);
dragController.makeDraggable(lb);
dragController.addDragHandler(new DragHandler() {
#Override
public void onPreviewDragStart(DragStartEvent event)
throws VetoDragException {}
#Override
public void onPreviewDragEnd(DragEndEvent event) throws VetoDragException {}
#Override
public void onDragStart(DragStartEvent event) {
}
#Override
public void onDragEnd(DragEndEvent event) {
// TODO Auto-generated method stub
DragContext context = event.getContext();
int x=context.mouseX;
int y= context.mouseY;
droper.add(context.selectedWidgets.get(0),x,y);
}
});
NameDropController dropController = new NameDropController(droper);
dragController.registerDropController(dropController);
dragController.setBehaviorDragProxy(true);
}
and my DropController class is:
public class NameDropController extends AbstractDropController{
public NameDropController(Widget dropTarget) {
super(dropTarget);
}
#Override
public void onDrop(DragContext context) {
int x=getDiff(getDropTarget().getAbsoluteLeft(), context.mouseX);
int y=getDiff(getDropTarget().getAbsoluteTop(), context.mouseY);
((AbsolutePanel)getDropTarget()).add(context.selectedWidgets.get(0),x,y);
System.out.print("("+context.mouseX+"::,::"+context.mouseY+")");
}
#Override
public void onMove(DragContext context){
}
private int getDiff(int val1,int val2){
return Math.abs(val1-val2);
}
}