code: public static JInternalDialog createDialog (
          JFrame frame, String title, JPanel content)
      {
          JInternalDialog dialog = new JInternalDialog(frame);
          dialog.setOpaque(false);
          if (title != null) {
              dialog.setTitle(title);
          }
          setContent(dialog, content);
          SwingUtil.centerComponent(frame, dialog);
          dialog.showDialog();
          return dialog;
      }
docs: Creates and shows an internal dialog with the specified title and
  panel.