code: protected void showWindow(final RenderContext renderContext) {
  		// Get current step
  		int current = UIContextHolder.getCurrent().getEnvironment().getStep();
  		// Get window current step (may have already been launched)
  		int window = getStep();
  		// Combine step counts to make previous window (if still open) invalid
  		setStep(window + current);
  
  		// TODO: This should be in a renderer, not included in this class
  		if (renderContext instanceof WebXmlRenderContext) {
  			PrintWriter writer = ((WebXmlRenderContext) renderContext).getWriter();
  
  			writer.print("\n<ui:popup");
  			writer.print(" url=\"" + WebUtilities.encode(getUrl()) + '"');
  			writer.print(" width=\"" + getWidth() + '"');
  			writer.print(" height=\"" + getHeight() + '"');
  
  			if (isResizable()) {
  				writer.print(" resizable=\"true\"");
  			}
  
  			if (isScrollable()) {
  				writer.print(" showScrollbars=\"true\"");
  			}
  
  			if (isShowMenuBar()) {
  				writer.print(" showMenubar=\"true\"");
  			}
  
  			if (isShowToolbar()) {
  				writer.print(" showToolbar=\"true\"");
  			}
  
  			if (isShowLocation()) {
  				writer.print(" showLocation=\"true\"");
  			}
  
  			if (isShowStatus()) {
  				writer.print(" showStatus=\"true\"");
  			}
  
  			if (getTop() >= 0) {
  				writer.print(" top=\"" + getTop() + '\'');
  			}
  
  			if (getLeft() >= 0) {
  				writer.print(" left=\"" + getLeft() + '\'');
  			}
  
  			writer.println("/>");
  		}
  	}
docs: Emits the mark-up which pops up the window.
  
  @param renderContext the RenderContext to send the output to.