title: Escape and unescape invalid characters
body: <p>This should be really easy. I have a string that i escape like the following:</p>
  
  <pre><code>string originalString = "M&amp;M";
  string escapedString = System.Security.SecurityElement.Escape(originalString);//M&amp;amp;M
  </code></pre>
  
  <p>Good so far</p>
  
  <pre><code>string unEscapedString = System.Security.SecurityElement.FromString(escapedString).Text;
  </code></pre>
  
  <p>Expecting to go back to M&amp;M but getting "object not set"</p>
  
  <p>Assuming string should be in xml format so any help on what i should do in this case would be helpful.</p>