code: public void actionPerformed(ActionEvent e)
      {
          if (e.getSource() == this)
          {
              Date dateTarget = this.getTargetDate();
              JCalendarPopup popup = JCalendarPopup.createCalendarPopup(this.getDateParam(), dateTarget, this, languageString);
              popup.addPropertyChangeListener(this);
          }
      }
docs: The user pressed the button, display the JCalendarPopup.
  @param e The ActionEvent.