title: Restrict work item fields to specific users in TFS 2010
body: <p>I am using TFS 2010 and I am customizing a work item type. I was wondering, if there is a way to restrict access to fields to users that are members of a group such as:</p>
  
  <pre><code>&lt;FIELD name="Created By" refname="System.CreatedBy" type="String" syncnamechanges="true" reportable="dimension" /&gt;
  
  &lt;FIELD name="Project Manager" refname="CustomField.ProjectManager" type="String" reportable="dimension"&gt;
      &lt;HELPTEXT&gt;The name of the project manager.&lt;/HELPTEXT&gt;
      &lt;SUGGESTEDVALUES expanditems="true" filteritems="excludegroups"&gt;
          &lt;LISTITEM value="[global]\Project Managers" /&gt;
      &lt;/SUGGESTEDVALUES&gt;
      &lt;WHENNOT field="System.CreatedBy" value="CustomField.ProjectManager"&gt;
          &lt;READONLY /&gt;
      &lt;/WHENNOT&gt;
  &lt;/FIELD&gt;
  </code></pre>
  
  <p><strong>EDIT</strong> Is there a way to restrict a specific user inside a group, for instance: Restrict project manager "John" from changing the field because that work item is not his project, but permit project manager "Jane" to change it because it is her project?</p>
  
  <p>The problem with the code above is that the <code>value</code> attribute only accepts a string value and does not recognize a field expression.</p>