title: TypeError: window.swaggerUi is undefined + Springfox.js
body: <p>Randomly, i am getting below js error when i try to hit swagger-ui url for my Spring Rest service.</p>
  
  <pre><code>TypeError: window.swaggerUi is undefined
  
  window.swaggerUi.headerView.trigger('update-swagger-ui', {
  </code></pre>
  
  <p>Most of the time, it is working fine and i am get response for all resources as expected.</p>
  
  <p>Am i missing something? In swagger integration to Spring Rest service.</p>
  
  <p>Version i am using is</p>
  
  <pre><code>    &lt;swagger2.version&gt;2.1.2&lt;/swagger2.version&gt;
      &lt;swagger-ui.version&gt;2.3.1&lt;/swagger-ui.version&gt;
  </code></pre>
  
  <p>Thanks in advance!</p>