Markup block - Gen<None> - 7 - (0:0,0)
    Tag block - Gen<None> - 7 - (0:0,0)
        Markup span - Gen<Markup> - [<foo />] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:5
            HtmlTokenType.OpenAngle;[<];
            HtmlTokenType.Text;[foo];
            HtmlTokenType.WhiteSpace;[ ];
            HtmlTokenType.ForwardSlash;[/];
            HtmlTokenType.CloseAngle;[>];
