title: Cannot display my rails 4 app in iframe even if 'X-Frame-Options' is 'ALLOWALL'
body: <p>I am trying to test a responsive design. I am using Rails 4. 
  I know it sets 'X-Frame-Options' to SAME ORIGIN. So I overrided it in development.rb using</p>
  
  <pre><code>config.action_dispatch.default_headers = {
      'X-Frame-Options' =&gt; 'ALLOWALL'
    }
  </code></pre>
  
  <p>and it worked. I checked out the network request in the Chrome console and it is as follows:</p>
  
  <p><img src="https://i.stack.imgur.com/jHjC7.png" alt="enter image description here"></p>
  
  <p>But still websites like responsive.is and responsinator.com give me below error:</p>
  
  <pre><code>Refused to display 'http://localhost:3000/' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'. about:blank:1
  </code></pre>
  
  <p>Whats going on??</p>