code: @Override
  	public void doRender(final WComponent component, final WebXmlRenderContext renderContext) {
  		WPopup popup = (WPopup) component;
  		XmlStringBuilder xml = renderContext.getWriter();
  		int width = popup.getWidth();
  		int height = popup.getHeight();
  		String targetWindow = popup.getTargetWindow();
  
  		xml.appendTagOpen("ui:popup");
  		xml.appendUrlAttribute("url", popup.getUrl());
  		xml.appendOptionalAttribute("width", width > 0, width);
  		xml.appendOptionalAttribute("height", height > 0, height);
  		xml.appendOptionalAttribute("resizable", popup.isResizable(), "true");
  		xml.appendOptionalAttribute("showScrollbars", popup.isScrollable(), "true");
  		xml.appendOptionalAttribute("targetWindow", !Util.empty(targetWindow), targetWindow);
  		xml.appendClose();
  		xml.appendEndTag("ui:popup");
  	}
docs: Paints the given WPopup.
  
  @param component the WPopup to paint.
  @param renderContext the RenderContext to paint to.