title: Override XHTML validation for Rich Text Fields in Sitecore
body: <p>I'm trying to embed some renderings as detailed in <a href="http://sitecorejohn.wordpress.com/2010/04/28/embed-renderings-maps-media-etc-in-sitecore-rich-text-editor-fields/" rel="nofollow">this article</a>. However when I try to add a rendering into a Rich Text field I get XHTML validation errors. I can't disable XHTML validation for the client so I wanted to extend the schema used for validation. This is stored in the /sitecore/shell/schemas directory.</p>
  
  <p>The markup for the rendering I'm trying to embed is:</p>
  
  <pre><code>&lt;smart:addresssnippet runat="server" /&gt;
  </code></pre>
  
  <p>I've tried to add a new schema for the smart namespace but this doesn't seem to work. When I go back to the HTML for the Rich Text field Sitecore has rewritten the code to be:</p>
  
  <pre><code>&lt;smart:addresssnippet runat="server" xmlns:smart="http://www.sitecore.net/xhtml"&gt;&lt;/smart:addresssnippet&gt;
  </code></pre>
  
  <p>This fails validation. Has anyone encountered this or a way to add renderings to the validation schema?</p>