// the coord where the user has double-clicked
int x = e.getX();
int y = e.getY();
// resolve the object if the user double-clicked on
// a cluster object.
Object obj = panel.resolveObject(x, y);
if (obj != null && (obj instanceof DefaultObject)) {
DefaultObject defObj = (DefaultObject) obj;
if (defObj.getLocation() != null) {
URL url;
try {