Comboboxcolumn in gridview 'almost' working... 'default' value doesn't display when initializing

Question

Using:
--Visual Studio 2010
--Winform app
--.net 4.0

I've got a Forms application that is using a comboboxcolumn in a gridview.  The data is sourced from an XML file but I need to add a column to the Gridview which is a 'drop-down' list from which the user can make various choices.

Everything seems to work (drop-down list created, user can select item from list, I can read selected item, etc; almost perfect).

The only thing that doesn't work is that upon initialization, I can't seem to display the default value.  I can set the default value, and I know it is set because I can retrieve the data which verifies indeed that the default has been set correctly.

But all I see in the gridview is a blank column when I start; if I select an item from the drop-down list, the selected item is displayed.


Basic code snippets here:

       // Read XML data
       AlarmTypes.dsAlarms.ReadXml(fsReadXml);

       // Bind data to gridview
       AlarmsGridView.DataSource = AlarmTypes.dsAlarms;


       //Create new comboboxcolumn control
       DataGridViewComboBoxColumn comboboxColumn = new DataGridViewComboBoxColumn();


       // initialize combobox list
       foreach (string s1 in ObservationNames)
               comboboxColumn.Items.AddRange(s1);


       // add control to gridview
       AlarmsGridView.Columns.Insert(0, comboboxColumn);



       // some stuff I've tried (among dozens of other things; following code sets default but it is still
       // not displayed upon initialization

       DataGridViewComboBoxCell cell = (DataGridViewComboBoxCell) AlarmsGridView.Rows[0].Cells[0];
       cell.Value = "berry";         // this is 3rd item in list  (and yes, 'berry' is spelled correctly in list)
       cell.Selected = true;

 Any ideas?

Thanks.