I'm trying to build grid with build in column filtering (using sencha gxt), here is my code:

public Grid<Stock> createGrid() {


    // Columns definition
    ColumnConfig<Stock, String> nameCol     = new ColumnConfig<Stock, String>(props.name(),     100,    "Company");

    // Column model definition and creation
    List<ColumnConfig<Stock, ?>> cl = new ArrayList<ColumnConfig<Stock, ?>>();
    cl.add(nameCol);
    ColumnModel<Stock> cm = new ColumnModel<Stock>(cl);

    // Data populating
    ListStore<Stock> store = new ListStore<Stock>(props.key());
    store.addAll(TestData.getStocks());


    // Grid creation with data
    final Grid<Stock> grid = new Grid<Stock>(store, cm);
    grid.getView().setAutoExpandColumn(nameCol);
    grid.setBorders(false);
    grid.getView().setStripeRows(true);
    grid.getView().setColumnLines(true);


    // Filters definition
    StoreFilterField<Stock> filter = new StoreFilterField<Stock>() {

        @Override
        protected boolean doSelect(Store<Stock> store, Stock parent, Stock item, String filter) {

           // Window.alert(String.valueOf("a"));

           String name = item.getName();
            name = name.toLowerCase();
            if (name.startsWith(filter.toLowerCase())) {
                return true;
            }
            return false;
        }
    };
    filter.bind(store);

    cm.addHeaderGroup(0, 0, new HeaderGroupConfig(filter, 1, 1));
    filter.focus();
    return grid;
}

My problem is: after I run this code, I cannot write anything to filter input, I'm using test data and classes (Stock.java and StockProperties.java) from this example: http://sencha.com/examples-dev/#ExamplePlace:filtergrid I try to put allert in doSelect method to check if this function was called, but it wasn't. Any idea will be welcome. Thanks.