A PopEndTag was called without A corresponding PushEndTag

I only met this while working on a Menu control, but who knows, maybe it occurs in other situations as well. Bottom line I wanted to create a CSS friendly Menu without using an adapter. So I inherited from Menu, did some stuff, then Kaboom! "A PopEndTag was called without A corresponding PushEndTag" error.

I could not determine where it cam from. The only helpful article on the net seemed to be one from a guy that also wanted to inherit from Menu. Strangely enough his problem only appeared in Design mode, while mine was a runtime thing. And weirder still, the problem was "solved" by the same ridiculous fix, that of calling an extra

base.RenderBeginTag(writer);

in my RenderBeginTag method override. However, his explanation that is all came from IControlDesignerAccessor did not solve anything for me. Menu only overrides the SetDesignModeState and GetDesignModeState methods from IControlDesignerAccessor and when I also overrode them and removed any code inside, I still got the error.

So, after an hour of searching, I solved it by overriding the Render method with

protected override void Render(HtmlTextWriter writer)
{
   if (this.Page != null)
   {
      this.Page.VerifyRenderingInServerForm(this);
   }
   if (this.Items.Count > 0)
   {
      this.RenderBeginTag(writer);
      this.RenderContents(writer);
      this.RenderEndTag(writer);
   }
}

which is the exact implementation from the original Menu source code, but without the 'false' parameter in RenderContents and RenderEndTag.

Hope it helps someone.