[Gtk-sharp-list] ComboBox Items Don't Display

[Jim Orcheson]

I am having a problem displaying items in a ComboBox. See the sample 
program below:

using System;
using Gtk;
namespace ComboBoxTest
{
     public class CombBoxTest
     {
         public static void Main()
         {
             Application.Init();
             CBWindow win = new CBWindow();
             win.ShowAll();
             Application.Run();
         }
     }

     public class CBWindow : Window
     {
         private ListStore store;

         public CBWindow() : base("ComboBox Test")
         {
             store = new ListStore(typeof(string));
             store.AppendValues("A");
             store.AppendValues("B");
             store.AppendValues("C");
             ComboBox cb = new ComboBox(store); // or ComboBox cb = new 
ComboBox(); cb.Model = store;

             cb.WidthRequest = 100;
             VBox vbox = new VBox();
             vbox.Add(cb);

             this.Add(vbox);
         }
     }
}

If instead of the code above I use:

             string[] data = {"A", "B", "C"};
             ComboBox cb = new ComboBox(data);

then the items are displayed, but neither the code in the sample above 
or the following will show the items. In these cases, the values are in 
the Model, they just won't display.

             ComboBox cb = new ComboBox();
             cb.AppendValues("A");
             cb.AppendValues("B");
             cb.AppendValues("C");

I guess I am missing something, but I can't determine what. The only 
example I found on the Internet used the string array for values, and 
this would be difficult to program because in my application there would 
be a variable number of items.

I am using mono 2.6.7 and gtk# 2.12.

Jim