将WPF4 Datagrid绑定到Empty Collection

I have a collection of objects which I am trying to bind to a DataGrid. When the collection has a lot of objects in it, it works fine. When the collection is empty, however, I see a blank row in the DataGrid, however, I cannot edit it. When I bind it to a collection which has an empty list, then two rows appear, and it is possible to edit the second row with the first empty, even though I have validation. I have tried both an ordinary List<>, and an ObservableCollection<>.I have a collection of objects which I am tryin