Here is what I am doing now and am having the same problem:



public boolean handleMouseEvent(MouseEvent e) {

        if (e.getButton() == MouseEvent.BUTTON3 && e.getID() ==

MouseEvent.MOUSE_CLICKED) {

            Point2D.Double p = new Point2D.Double(e.getX(), e.getY());



            Bag[] hitObjects = objectsHitBy(p);



            boolean empty = true;

            for (int i = 0; i < hitObjects.length; i++)

                if (hitObjects[i].numObjs > 0) {

                    empty = false;

                    break;

                }



            if (empty) {

                addPopup.setEvent(e);

                addPopup.show(this, e.getX(), e.getY());

                return true;

            } else {

                removePopup.removeAll();

                for (int x = hitObjects.length - 1; x >= 0; x--)

                    for (int i = 0; i < hitObjects[x].numObjs; i++) {

                        LocationWrapper wrapper = (LocationWrapper)

(hitObjects[x].objs[i]);

                        final Object obj = wrapper.getObject();

                        removePopup.add(new AbstractAction("Delete " +

obj.toString()) {

                            @Override

                            public void actionPerformed(ActionEvent e) {

                                synchronized (state.schedule) {

                                    IAgent agent = (IAgent) obj;

                                    if (agent instanceof Manager &&amp;

state.managers().length == 1) {

                                       

JOptionPane.showMessageDialog(InteractiveDisplay2D.this, "Need at least one

manager",

                                                "Manager Needed",

JOptionPane.ERROR_MESSAGE, null);

                                        return;

                                    }



                                    removeAgent(agent);

                                    if (agent instanceof Manager) {

                                       

ui.dataset.removeSeries(agent.toString() + " Profit");

                                        for (Restocker restocker :

((Manager) agent).getRestockers())

                                            removeAgent(restocker);

                                        for (CokeMachine machine :

((Manager) agent).getMachines())

                                            removeAgent(machine);

                                    }

                                }

                            }

                        });

                    }

            }

            removePopup.show(this, e.getX(), e.getY());

            return true;

        } else

            return super.handleMouseEvent(e);

    }



    private void removeAgent(IAgent agent) {

        for (IBehavior behavior : agent.getBehaviors())

            if (behavior.getStopper() != null)

                behavior.getStopper().stop();

        Manager[] managers = state.managers();

        for (Manager manager : managers) {

            if (agent instanceof Restocker)

                manager.getRestockers().remove(agent);

            else if (agent instanceof CokeMachine)

                manager.getMachines().remove(agent);

        }

        state.getAgents().remove(agent);

        state.agentGrid.remove(agent);

        ui.controller.refresh();

    }



IAgent and IBehavior are wrappers over MASON.