code: protected String startColSpanDiv(ResponseWriter rw, SelectBooleanCheckbox selectBooleanCheckbox) throws IOException {
          String clazz = Responsive.getResponsiveStyleClass(selectBooleanCheckbox, false);
          if (clazz != null && clazz.trim().length() > 0) {
              rw.startElement("div", selectBooleanCheckbox);
              rw.writeAttribute("class", clazz, "class");
          }
          return clazz;
  	}
docs: Start the column span div (if there's one). This method is protected in
  order to allow third-party frameworks to derive from it.
  
  @param rw
  the response writer
  @param selectBooleanCheckbox
  the component to render
  @throws IOException
  may be thrown by the response writer