title: extjs filter grid data in column header textfield
body: <p>I am trying to understand how the grid header filter works in the column header textfield.</p>
  
  <p>replicated kitchen sink example, can't see the textfield inside the column header.</p>
  
  <p><a href="http://jsfiddle.net/srikanthradix/ghzD9/2/" rel="nofollow">http://jsfiddle.net/srikanthradix/ghzD9/2/</a></p>
  
  <p>I defined the company column which I would like to filter</p>
  
  <pre><code>{
                  text: 'Company (Filter)',
                  sortable: false,
                  dataIndex: 'company',
                  width: 120,
                  locked: true,
                  editor: {
                      xtype: 'textfield'
                  },
                  items: {
                      xtype: 'textfield',
                      flex : 1,
                      margin: 2,
                      enableKeyEvents: true,
                      listeners: {
                          keyup: function() {
                              var store = this.up('tablepanel').store;
                              store.clearFilter();
                              if (this.value) {
                                  store.filter({
                                      property     : 'company',
                                      value         : this.value,
                                      anyMatch      : true,
                                      caseSensitive : false
                                  });
                              }
                          },
                          buffer: 500
                      }
                  }
              }
  </code></pre>
  
  <p>and also added the basic setup like setpath, requires, and features</p>
  
  <pre><code>Ext.Loader.setPath('Ext.ux', 'http://cdn.sencha.com/ext-4.2.0-gpl/examples/ux/');
  
  Ext.require([
      'Ext.grid.*',
      'Ext.data.*',
      'Ext.util.*',
      'Ext.state.*',
      'Ext.ux.grid.FiltersFeature'
  ]);
  </code></pre>
  
  <p>inside the grid</p>
  
  <pre><code> features: [{
              ftype: 'filters'
          }],
  </code></pre>
  
  <p>Could you suggest if I am missing anything else?</p>