code: private static Modal getModal(RootPaneContainer rootPane) {
  	synchronized (modals) {
  	  Modal modal = modals.get(rootPane);
  	  if (modal == null) {
  		modal = new Modal(rootPane);
  		modals.put(rootPane, modal);
  	  }
  	  return modal;
  	}
    }
docs: Get the modal of a specific frame
  
  @param rootPane
  the RootPaneContainer with a modal
  @return {@link Modal}