/** @param ev */
 @Override
 public void onMouseReleased(MapMouseEvent ev) {
   // avoid the zooming window at the time scroll button pan action.
   if (dragged
       && !ev.getPoint().equals(startDragPos)
       && ev.getButton() != java.awt.event.MouseEvent.BUTTON2) {
     dragged = false;
     Envelope2D env = new Envelope2D();
     env.setFrameFromDiagonal(startDragPos, ev.getWorldPos());
     this.onRectangleFinished(env);
   }
 }
 /**
  * Records the map position of the mouse event in case this button press is the beginning of a
  * mouse drag
  *
  * @param ev the mouse event
  */
 @Override
 public void onMousePressed(MapMouseEvent ev) {
   startDragPos.setLocation(ev.getWorldPos());
 }