title: Can't append Element/Component to a Extjs Panel
body: <p>I am trying to append a button to a panel. First I create the panel, and render it to <strong>Ext.getBody()</strong>. That seems to work fine, but then I want to render a button to that panel, and it gives this error : </p>
  
  <blockquote>
    <p>Uncaught TypeError: Cannot read property 'dom' of null</p>
  </blockquote>
  
  <p>Here is the code :</p>
  
  <pre><code>Ext.onReady(function () {
  
      var p = Ext.create('Ext.Panel',{
          renderTo:Ext.getBody(),
          html:'myPanel'
      })
  
  
      Ext.create('Ext.Button', {
          text: 'Click me!!!!',
          renderTo: p,
          handler: function() {
              alert('You clicked the button!')
          }
      });
  });
  </code></pre>
  
  <p>Fiddle here :</p>
  
  <p><a href="https://fiddle.sencha.com/#fiddle/694" rel="nofollow">https://fiddle.sencha.com/#fiddle/694</a></p>