title: My textfield is getting cleared automatically
body: <p>I am new to iOS development. I am having a weird situation, not every time but very often. My textfield is getting cleared automatically when I come back to the same screen using back button. Code as:</p>
  
  <pre><code>self.navigationController?.popViewControllerAnimated(true)
  </code></pre>
  
  <p>Problem happens in both simulator and device.</p>