title: Extjs view alias / xtype not defined in controller
body: <p>I have a view which contains a tab control with 2 tabs. I have defined an alias for each tab, in this format:</p>
  
  <pre><code>alias: 'widget.contenttab'
  </code></pre>
  
  <p>I am trying to access 'contenttab' in the controller but it says it is not defined:</p>
  
  <pre><code>contenttab is not defined
  </code></pre>
  
  <p>I am trying to set the html content of the tab in a select handler in the controller:</p>
  
  <pre><code>Ext.define('BP.controller.Induction', {
  extend: 'Ext.app.Controller',
  
  views: [
      'induction.Binder',
      'induction.LeftPage',
      'induction.RightPage',
  ],
  
  stores: [
      'Sections',
      'Categories',
      'Tasks'
  ],
  
  models: [
      'Section',
      'Category',
      'Task'
  ],
  
  
  init: function() {
      this.control({
          'grid[xtype=categorygrid]': {
              itemclick: this.onItemClick 
          }
      });
      console.log('Initialized Induction!');
  },
  
  
  onItemClick: function(e, d) {
      console.log(d.data.category_id);
      this.getCategoriesStore().load({params:{'id':d.data.category_id}}, {
          success: function(category) {
              console.log("Category: " + category.get('name'));
          },
          error: function(e) {
              console.log(e);
          }
      });
      contenttab.html = 'test'; // produces error
  
  }
  });
  </code></pre>
  
  <p>The 'contenttab' is within my RightPage view. The line which produces an error ultimately needs to reside within the success callback function - but this isn't getting fired (I have created another question here for that issue <a href="https://stackoverflow.com/questions/13353236/extjs-store-load-success-handler-not-getting-fired">Extjs store load success handler not getting fired</a></p>
  
  <p>Any guidance appreciated, thanks.</p>