String size = children.header.consumeRequiredDoubleAttribute("size");
String html = children.header.consumeInnerHtml(htmlInt);
writer.addStatement("%s.add(%s, %s, true, %s);", fieldName,
childFieldName, writer.declareTemplateCall(html), size);
} else if (children.customHeader != null) {
XMLElement headerElement = children.customHeader.consumeSingleChildElement();
String size = children.customHeader.consumeRequiredDoubleAttribute("size");
if (!writer.isWidgetElement(headerElement)) {
writer.die(headerElement, "Is not a widget");
}