解决方法
实现NSTableViewDelegate方法
tableView:shouldReorderColumn:toColumn:以控制此行为.从
documentation开始：
When a column is initially dragged by the user,the delegate is first called with a newColumnIndex value of
-1. ReturningNOwill disallow that column from being reordered at all. ReturningYESallows it to be reordered,and the delegate will be called again when the column reaches a new location.