 
 import mx.collections.ICollectionView;
 import mx.collections.IList;
+import mx.collections.ISort;
+import mx.collections.ISortField;
 import mx.collections.Sort;
-import mx.collections.SortField;
 import mx.core.EventPriority;
 import mx.core.IFactory;
 import mx.core.IIMESupport;

        if (!dataProvider)
            return false;
        
        var sort:Sort = dataProvider.sort;
        if (sort)
            sort.compareFunction = null;
        else

                return null;
            
            const isComplexDataField:Boolean = (dataField && (dataField.indexOf(".") != -1));
            var sortField:ISortField = null;
            var sortDescending:Boolean = col.sortDescending;
            
            // Check if we just sorted this column.
