title: XamlReader.Parse exception
body: <p>I have a problem with parsing a xaml string</p>
  
  <pre><code>(FlowDocument)(System.Windows.Markup.XamlReader.Parse(string));
  </code></pre>
  
  <p>Got this exception</p>
  
  <pre><code>'Cannot create unknown type '{http://schemas.microsoft.com/winfx/2006/xaml/presentation}UnderLine'.' Line number '3' and line position '13'.
  </code></pre>
  
  <p>string looks like this</p>
  
  <pre><code>&lt;FlowDocument xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"&gt;&lt;Paragraph&gt;&lt;Bold&gt;text&lt;/Bold&gt;&lt;/Paragraph&gt;
  &lt;Paragraph&gt;&lt;Italic&gt;text&lt;/Italic&gt;&lt;/Paragraph&gt;
  &lt;Paragraph&gt;&lt;UnderLine&gt;text&lt;/UnderLine&gt;&lt;/Paragraph&gt;
  ...
  &lt;/FlowDocument&gt;
  </code></pre>
  
  <p>Everything else except underline works. Anybody knows where is the problem?</p>