org.zkoss.zkplus.embed.Renders provides an option to control whether to generate addtion DOM element for the page

Currently, Renders.render(ServletContext ctx, HttpServletRequest request, HttpServletResponse response, Richlet richlet, String path, Writer out) does not generate an additional enclosing DOM element to represent the page. It is OK in the most cases. However, something it is more convenient if it has such DOM element. For example, there are multiple root elements and we'd like to remove them all.