title: I can't add the Source button to CKEditor 4's toolbar
body: <p>I'm having trouble adding the Source button to CKEditor 4's toolbar. I just downloaded the new CKEditor today.</p>
  
  <p>I'm using a config object named oConfig:</p>
  
  <pre><code>oConfig.toolbar = 'Custom';
  oConfig.toolbar_Custom = [
    ['Bold', 'Source', 'Italic']
  ];
  </code></pre>
  
  <p>The toolbar shows up with only the Bold and Italic buttons. <a href="http://docs.ckeditor.com/#!/api/CKEDITOR.config-cfg-toolbar">This example</a> from CKEditor's docs tells me it should be working.</p>