             return;
 
         var view:ICollectionView = ICollectionView(dataProvider);
-        var sort:Sort = view.sort;
+        var sort:ISort = view.sort;
         if (!sort)
         {
             sortIndex = lastSortIndex = -1;

        // do the sort if we're allowed to
        if (c.sortable)
        {
            var s:Sort = collection.sort;
            var f:SortField;
            if (s)
            {
                s.compareFunction = null;

        }

        // fields.length == 1, so the collection is sorted on a single field.
        var sortField:ISortField = fields[0];
        var n:int = _columns.length;
        sortIndex = -1;
        for (var i:int = 0; i < n; i++)
