title: IntelliJ IDEA, how to enable preview tool
body: <p><img src="https://i.stack.imgur.com/kxrxG.png" alt="enter image description here"></p>
  
  <p>Why it's happening ?
  How can I enable it ?
  <strong>IntelliJ IDEA version: 12.1.6</strong> </p>
  
  <hr>
  
  <p><strong>PICTURE UPDATED</strong></p>