title: Extjs Menu insert new items with override
body: <p>I have a menu which is defined like that:</p>
  
  <pre><code>Ext.define('MyApp.FileBrowserContextMenu', {
      extend: 'Ext.menu.Menu',
  
      initComponent: function() {
          var me = this;
  
          Ext.applyIf(me, {
              items: [
                  {
                      xtype: 'menuitem',
                      text: 'Edit',
                      listeners: {
                          click: {
                              fn: me.onMenuitemClick,
                              scope: me
                          }
                      }
                  },
              ]
          });
  
          me.callParent(arguments);
      },
  
      onMenuitemClick: function(item, e, options) {
          var server = this.record;
          var win = Ext.create('widget.ServerWindow', {
              record: server
          });
          win.show();
      }
  
  });
  </code></pre>
  
  <p>I would like to add new items after the definition, so I try like that:</p>
  
  <p>First I defined the new MenuItem:</p>
  
  <pre><code>Ext.define('MyApp.GitMenuItem', {
      extend: 'Ext.menu.Item',
      alias: 'widget.gitmenuitem',
  
      text: 'Git',
  
      initComponent: function() {
          var me = this;
  
          Ext.applyIf(me, {
              menu: {
                  xtype: 'menu',
                  items: [
                      {
                          xtype: 'menuitem',
                          text: 'Commit',
                          listeners: {
                              click: {
                                  fn: me.onMenuitemClick,
                                  scope: me
                              }
                          }
                      },
                  ]
              }
          });
  
          me.callParent(arguments);
      },
  
      onMenuitemClick: function(item, e, options) {
  
      },
  
  });
  </code></pre>
  
  <p>Then I try to attach the new menu item:</p>
  
  <pre><code>Ext.override(MyApp.FileBrowserContextMenu, {
      initComponent: function () {
          var me = this;
          this.callParent();
          me.items.items.push(Ext.create('widget.gitmenuitem'));
      }
  });
  </code></pre>
  
  <p>It seems to work, because the new MenuItem appears, but when I go over, Then new Item should appears but I get this error:</p>
  
  <p>Uncaught TypeError: Cannot set property 'activeChild' of undefined </p>
  
  <p>Any ideads ?</p>