title: keyup event not getting fired on setValue() of the textfield
body: <p>I am using two tabpanels (for e.g <strong>T1</strong> and <strong>T2</strong>). Their are two textfields and submit button in <strong>T2</strong> as shown:</p>
  
  <pre><code>xtype: 'form',
  title: 'Search',
  id:'searchref',                          
  items: [
      {
          xtype: 'textfield',
          fieldLabel: 'reference1',
          id:'reference1',     
          enableKeyEvents:true,
          listeners:{
              keyup:function(){
                  Ext.getCmp('Submit').enable();
                  Ext.getCmp('reference2').disable();
                  if(Ext.getCmp('reference1').getValue() == "" )
                  {
                      Ext.getCmp('Submit').disable();
                      Ext.getCmp('reference2').enable();
                  }                                                       
              }
          }
       },
       {
              xtype: 'textfield',
              fieldLabel: 'reference2',
              id:'reference2',     
              enableKeyEvents:true,
              listeners:{
                  keyup:function(){
                      Ext.getCmp('Submit').enable();
                      Ext.getCmp('reference1').disable();
                      if(Ext.getCmp('reference2').getValue() == "" )
                      {
                          Ext.getCmp('Submit').disable();
                          Ext.getCmp('reference1').enable();
                      }                                                       
                  }
              }
        },
  
      {
          xtype: 'button',
          text: 'Submit',
          disabled:true,  
          id:'Submit',                            
      }   
  ]
  </code></pre>
  
  <p>In my <strong>T1</strong>, I am trying to do as shown:</p>
  
  <pre><code>Ext.getCmp('tabpanel').setActiveTab(1);
  Ext.getCmp('reference1').setValue(RefNo);
  </code></pre>
  
  <p><strong>MY PROBLEM:</strong></p>
  
  <p>The keyup event listener not getting fired on setting the value of textfield from <strong>T1</strong></p>
  
  <p>Please help me resolve this.<br>
  Any help is appreciated. Thanks.</p>