title: ExtJS 4 add custom filter to GridPanel that uses reconfigure method
body: <p>I am trying to solve a problem with a functionality I need to implement for a grid. This grid should use a custom "filter" which extends from "Ext.ux.grid.FiltersFeature", this component works fine since it works for other grids I implemented. the problem is that the grid I want to implement now, does not load it columns at the first moment like the previous I implemented; this grid has a controller which uses a "reconfigure" method to create the columns based on a "store".</p>
  
  <p>For instance:</p>
  
  <pre><code>grid.reconfigure(store, cols);
  </code></pre>
  
  <p>I've seen many examples on how to add individual filters and so on, but they use the <code>"ftype: "filters"</code>, I do need to use my <code>"ftype: mycustomfilter"</code> specifically. Any idea on how can I do this? I tried everything, but nothing seems to be working and I am stucked with this.</p>
  
  <p>Here's some of my code:</p>
  
  <p><strong>Portion of code in the Controller:</strong></p>
  
  <pre><code> if (refreshGrid) {
          var cols = this.createGridColumns();
          //This is the method that loads my column based on the store 
          //(which I retrieve from Ajax request)
          grid.reconfigure(store, cols);
          oldStore.destroyStore();
      } else {
          this.mergeFn.call(this, values, store);
          grid.view.refresh();
      }
  </code></pre>
  
  <p>What I tried to do is to add a feature after reconfiguring the grid:</p>
  
  <pre><code>grid.reconfigure(store, cols);
  //Then I add this portion of code:
  grid.features = [{
    ftype: 'customfilterfeature',
    autoReload: false,
    local: true,
    filters: [{type: 'list', dataIndex: 'activity'},
              {type: 'list', dataIndex: 'datetime'}]  
    }]
  </code></pre>
  
  <p>Does anybody have an idea on how can I achieve this? Because this is not working at all, the filter is not being displayed. Any help will be really appreciated. Thanks in advance.</p>