MarkupBlock - [0..29)::29 - [<foo>blah blah blah blah blah]
    MarkupTagBlock - [0..5)::5 - [<foo>]
        MarkupTextLiteral - [0..5)::5 - [<foo>] - Gen<Markup> - SpanEditHandler;Accepts:None
            OpenAngle;[<];
            Text;[foo];
            CloseAngle;[>];
    MarkupTextLiteral - [5..29)::24 - [blah blah blah blah blah] - Gen<Markup> - SpanEditHandler;Accepts:Any
        Text;[blah];
        Whitespace;[ ];
        Text;[blah];
        Whitespace;[ ];
        Text;[blah];
        Whitespace;[ ];
        Text;[blah];
        Whitespace;[ ];
        Text;[blah];
