title: ExtJS4: Store created in initComponent is undefined in form panel
body: <p>After having gone back to the ExtJS4 docs and copying in their examples line for line trying to troubleshoot where I could have gone wrong, I am stumped.  Sniffing around the issue of initComponent being in an unfortunate order of operations.</p>
  
  <p>The store that is being defined is 1) not populating the field and 2) is said to be undefined after trying to call it from the field listener.  </p>
  
  <p>I am defining a store as such in initComponent,</p>
  
  <pre><code>Ext.define('X.view.NewLogWindow', {
  extend: 'Ext.window.Window',
  xtype:'newlogwindow',
  itemId: 'newLogWindow',
  width: 300,
  height: 140,
  modal: true,
  title: 'Create Log',
  layout: 'fit',
  initComponent: function() {
  
      this.monthStore = Ext.create('Ext.data.Store', {
          fields : [
              {name : 'id', type : 'int'}, {name : 'month', type : 'string'}
          ],
          autoLoad: true,
          data : [
              {"id" : 0, "month" : "January"},
              {"id" : 1, "month" : "February"},
              {"id" : 2, "month" : "March"},
              {"id" : 3, "month" : "April"},
              {"id" : 4, "month" : "May"},
              {"id" : 5, "month" : "June"},
              {"id" : 6, "month" : "July"},
              {"id" : 7, "month" : "August"},
              {"id" : 8, "month" : "September"},
              {"id" : 9, "month" : "October"},
              {"id" : 10, "month" : "November"},
              {"id" : 11, "month" : "December"}
          ]
      });
  
      var x = 'fixme';
  
      console.log(this.monthStore);
      console.log(x);
  
  
      this.callParent();
  
  
  }
  </code></pre>
  
  <p>Then, I am assigning the store to the combobox in the form panel as such:</p>
  
  <pre><code>items: [
      {
          xtype: 'form',
          margin: 10,
          border: false,
          defaults: {allowBlank: false},
          items: [
              {
                  xtype: 'combobox',
                  fieldLabel: 'Log Month',
                  store: this.monthStore,
                  queryMode : 'local',
                  displayField: 'month',
                  valueField: 'id',
                  listeners: {blur: function(field)
                  {
                      console.log(this.monthStore);
                      console.log(this.x);
                      }
  
                  }
              }
          ]
      }
  ]
  </code></pre>
  
  <p>Here are the outputs from my console logging:</p>
  
  <pre><code>constructor NewLogWindow.js:40
  fixme NewLogWindow.js:41
  undefined NewLogWindow.js:74
  undefined NewLogWindow.js:75
  </code></pre>
  
  <p>Thanks in advance.</p>