title: sencha touch :Trying to add a null item as a child of Container with itemId/id: ext-comp-1050
body: <p>I am new to Sencha Touch. I have an existing web application I have to improve.</p>
  
  <p>I created a new panel and try to add items to an existing panel but I get an error when trying to add a NULL element as a child of Container itemId/id: ext-comp-1050</p>
  
  <p>My code is as follows</p>
  
  <pre><code>Myapp.views.mainView = new Ext.extend(Ext.Panel, {
     initComponent: function() {
        this.items = [
            Myapp.views.welcomePanel, // new panel I am trying to add
            Myapp.views.settingsView,
            Myapp.views.placePopup,
            Myapp.views.newsPanel
        ];
        this.dockedItems = [];
        this.cardAnimation='slide';
        this.html = null;
        this.fullscreen = true;
        this.layout = 'card';
        this.align = 'stretch';
        Myapp.views.mainView.superclass.initComponent.call(this); 
    }
  });
  </code></pre>
  
  <p>and the code of welcome Panel is</p>
  
  <pre><code>Myapp.views.welcomePanel = new Ext.Panel({
      frame:true,
      autoHeight:true,
      collapsible:true,
      layout:'card',
      items:[
         Myapp.views.mapPlaces,
         Myapp.views.listOfPlaces
      ],
      dockedItems:[
         Myapp.views.mainToolBar,
         Myapp.views.changerPanelsToolbar
      ]
  });
  </code></pre>
  
  <p><code>Myapp.views.mapPlaces, Myapp.views.listOfPlaces, Myapp.views.mainToolBar, Myapp.views.changerPanelsToolbar</code></p>
  
  <p>are pre-existing &amp; working without problem</p>
  
  <p>Please help</p>