title: Facebook canvas Iframe App authentication problem
body: <ol>
  <li>I am in the conversion process of facebook app from fbml to iframe.</li>
  </ol>
  
  <p>Now i am testing using few iframe pages.</p>
  
  <pre><code>$user = $facebook-&gt;require_login();
  </code></pre>
  
  <p>It gives the current user logged in. Once it get the variable from the facebook.com it saves in cookie by the PHP API provided by facebook).
  I logged out using another tab of facebook and i tryed using my app without refreshing the whole site (by just using the links inside my app). It still gives the <code>$user</code> variable. </p>
  
  <p>It indicates that user has logged in instead of user logged out.</p>
  
  <p>Please help me out. I want my app secured.</p>
  
  <ol start="2">
  <li>It looks my iframe app accessible when we select "open this frame in new window". 
  I need a solution for this too.</li>
  </ol>
  
  <p>Thanks in advance.</p>