title: lookup in Ext.StoreManager.lookup is not defined
body: <p>This is my view:</p>
  
  <pre><code>Ext.define('MyApp.view.Login.LoginForm',{
      extend: 'Ext.form.Panel',
      alias: 'loginForm',
      requires: ['Ext.form.FieldSet', 'Ext.Img'],
      config: {
          items: [
              {
                  xtype: 'fieldset',
                  items: [
                      {
                          xtype: 'textfield',
                          name: 'username',
                          required: true
                      },{
                          xtype: 'textfield',
                          name: 'password',
                          required: true,
                          inputType: 'password'
                      },{
                          xtype: 'selectfield',
                         //*****************the problem is here****************
                          store: Ext.StoreManager.lookup('MyApp.store.Tables')
                          //store: Ext.StoreManager.lookup('Tables')
                      }
                  ]
              },{
                  xtype: 'button',
                  text: 'Login',
              }
          ]
      }
  });
  </code></pre>
  
  <p>It says that it cannot use <code>lookup of undefined</code>, so I'm thinking that MyApp doesn't see Ext.StoreManager.</p>
  
  <p>I've also tried <code>Ext.data.StoreManager.lookup</code> and <code>Ext.StoreMgr</code>.
  BTW. the store really exist.</p>