title: Extjs Combo - type text header and it will be focus to select
body: <p>I have 'xtype: combe' like <b><a href="http://jsfiddle.net/KYRhC/" rel="nofollow">http://jsfiddle.net/KYRhC/</a></b></p>
  
  <pre><code>{
          xtype        : 'combo',
          fieldLabel   : 'Letter',
          store        : mySimpleStore,
          displayField : 'name',
          typeAhead    : true,
          autoSelect: true,
          triggerAction:  'all',
          forceSelection: true,
  
          editable:       false,
          mode         : 'local'
      }
  </code></pre>
  
  <p>I want when i click to selectbox and type header of text and it will be focus to select 
  example type d -> D will focus to select
  <br> I have option <b>typeAhead    : true,</b> but not working.</p>