// this one does not work in my case
 
 new Ext.TabPanel({
   activeTab:0,
   defaults:{autoHeight: true, autoScroll: true},
   items:[{
      title: 'Defined',
      items: qtgrid1
   },{
      title: 'Undefined',
      listeners: {activate: function() {
        // some code
      }},
      items: qtgrid2
   }]
 })
 
 
 // here I save the intermediate container, and this tab panel renders fine.
 // However, I do not get to set the caption of the tab sheets. As a result, 
 // the tab sheets have empty caption and look very small.
 
 new Ext.TabPanel({
   activeTab:0,
   defaults:{autoHeight: true, autoScroll: true},
   items:[
     qtgrid1,
     qtgrid2
   ]
 })