title: Migrate from extJS 4 to extJS 5 : property undefined
body: <p>While trying to update my application from ExtJS4 to ExtJS5, I went into this error :</p>
  
  <pre><code>Uncaught TypeError: Cannot read property 'get' of undefined 
  </code></pre>
  
  <p>With the following code : </p>
  
  <pre><code>Ext.onReady(function () {
      Ext.require([
          'Ext.util.Cookies'
      ]);
      top.Dictionary.setDictionary(fr_FR);
  
      var formUserNameValue = "";
      if (Ext.util.Cookies.get('userName')) { &lt;&lt;&lt;&lt; the error occurs here
          formUserNameValue = Ext.util.Cookies.get('userName');
      }
  </code></pre>
  
  <p>And the index.html page :</p>
  
  <pre><code>&lt;meta http-equiv="X-UA-Compatible" content="IE=edge"&gt;
  
  &lt;title&gt;Login&lt;/title&gt;
  
  &lt;!-- Importation ExtJS --&gt;
  &lt;script type="text/javascript" src="../../ext-5.0.0/ext-debug.js"&gt;&lt;/script&gt;
  &lt;link rel="stylesheet" href="../../ext-5.0.0/packages/ext-theme-neptune/build/resources/ext-theme-neptune-all.css"/&gt;
  
  &lt;script type="text/javascript" src="app.js"&gt;&lt;/script&gt;
  
  &lt;!-- Importation des dictionnaires --&gt;
  &lt;script type="text/javascript" src="dictionary/fr_FR.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="dictionary/en_EN.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p></p>
  
  <p>Do you have any idea where that could come from ?</p>