title: Extjs4, How to update window bbar(toolbar)?
body: <p>I want to update Extjs window bbar(toolbar) dynamically, but I don't know how should I make it work, </p>
  
  <p>Example Code :</p>
  
  <pre><code>var myWin = Ext.create('Ext.window.Window', {
      modal: true,
      layout: 'fit',
      items: {
      // panel
      },
      bbar: ['-&gt;', {
      xtype: 'buttongroup',
      items: [{
          text: 'Cancel',
          handler: function () {
          invoicingWin.destroy();
          }
      }]
      }, {
      xtype: 'buttongroup',
      items: [{
          text: 'Continue',
          handler: function () {
  
          var test = new Ext.Toolbar({
              dock: 'bottom',
              items: ['-&gt;', { html: "Close"}]
          });
  
          //  !! I want to replace this window bbar to test(toolbar)
  
          } // btn handler
      }]// items
      }]
  }).show();
  </code></pre>
  
  <p>Anybody know, please help me.</p>
  
  <p>Thank you!</p>