docs: private JPanel getPanelParam() {
          if (panelParam == null) {
              panelParam = new JPanel();
              panelParam.setLayout(new CardLayout());
              panelParam.setPreferredSize(new java.awt.Dimension(300, 300));
              panelParam.setBorder(javax.swing.BorderFactory.createEmptyBorder(0, 0, 0, 0));
          }
          
          return panelParam;
      }