title: ASP.Net MVC Authorisation action filter
body: <p>I'm trying to understand how error handling works when using the Authorize [Authorize] Action Filter in MVC Preview 4.</p>
  
  <p>I have an action that looks like this:</p>
  
  <pre><code>[Authorize(Roles = "DOMAIN\\NOTAUTHORISED_ROLE" )]
  [HandleError]
  public ActionResult NeedAuthorisation()
  {
      throw new NotImplementedException();
  }
  </code></pre>
  
  <p>When I visit the url: <code>http://localhost:2197/testAuthorisation/NeedAuthorisation</code>, I get a blank page in my browser. In Firebug I can see that a request was made and a response-status of <code>401 - Unauthorised</code> has been returned. But I'm not being redirected or having a customError returned. Everything works as expected when using a role that I'm authorized for.</p>
  
  <p>This is using Windows authentication. I'm in the middle of writing some code to try out Forms authentication to see if I get the same issue.
  I have <code>&lt;customerrors mode="On"/&gt;</code> set and have created error pages, both in the testAuthorisation folder and the Shared folder.</p>