I am using Cocoa framework with Obj C. I have a NSTableView whose columns are bind to NSArrayController's arranged object's properties. Table view allows sorting of columns manually by user. Its working fine. Now, my NSArrayController's contents will be updated every 5 minutes. During update, old objects of array controller will be deleted and added again. So, automatically my table view contents changes accordingly. But its not maintaining the sorting order that it previously has. Can some body suggest me how to update the table view without loosing the sorting order?