title: Problem setting content control with OpenXML SDK 2.0
body: <p>I have a Word 2007 doc with content control, title and tag set to "Control1" and the value "X". I am trying to change the value of Control1 to "Y"</p>
  
  <pre><code>  string sdtName = "Control1";
    SdtBlock sdt = mainPart.Document.Descendants&lt;SdtBlock&gt;()
              .Where(s =&gt;
              s.GetFirstChild&lt;SdtProperties&gt;().GetFirstChild&lt;Alias&gt;().Val.Value
              .Equals(sdtName)).First();
  
    Response.Write(sdt.InnerXml);
    //results in X
    sdt.InnerXml = "Y";
  </code></pre>
  
  <p>X is displayed correctly, but when the InnerXml is set to "Y" it results in X being deleted from the document</p>