title: ckeditor removing empty span automatically
body: <p>i am using ckeditor and i have vary strange issue.</p>
  
  <p>it remove automatically empty <code>&lt;span&gt;</code> for example</p>
  
  <pre><code> &lt;span class="new-class"&gt;&lt;/span&gt;
  </code></pre>
  
  <p>removed automatically.</p>
  
  <p>i am searching for solution for last 2 days but no success. i try to put following code in </p>
  
  <p>config.js</p>
  
  <pre><code>CKEDITOR.config.allowedContent = true;
  </code></pre>
  
  <p>but no success.</p>
  
  <p>i also add following code in html where i use ckeditor but no success.</p>
  
  <pre><code>   &lt;script&gt;     
  var editor = CKEDITOR.replace( 'editor1', {
  allowedContent: true,
      } );
     &lt;/script&gt;    
  </code></pre>
  
  <p>thanks</p>