docs: private JPanel getPanelHeadline() {
          if (panelHeadline == null) {
              panelHeadline = new JPanel();
              panelHeadline.setLayout(new BorderLayout(0, 0));
  
              txtHeadline = getTxtHeadline();
              panelHeadline.add(txtHeadline, BorderLayout.CENTER);
  
              JButton button = getHelpButton();
              panelHeadline.add(button, BorderLayout.EAST);
          }
          
          return panelHeadline;
      }