docs: public void printHtmlHeading(PrintWriter out)
      {
          if (this.getScreenField().getConverter() != null)
              super.printHtmlHeading(out);
          else if (this.getScreenField().getParentScreen() instanceof GridScreen)
          { // These are command buttons such as "Form" or "Detail"
              String strImage = "Form";
              if (((SButtonBox)this.getScreenField()).getImageButtonName() != null)
                  strImage = ((SButtonBox)this.getScreenField()).getImageButtonName();
              out.println("<th align=\"center\" valign=\"center\"><img src=\"" + HtmlConstants.IMAGE_DIR + "buttons/" + strImage + ".gif\" width=\"16\" height=\"16\" alt=\"Open this record\"></th>");
          }
      }