Can't get my ComboButtDrop to work in my Hello Form

I am trying to build a panel that works like the Properties panel but have been running into a ComboBoxCell problem. In looking though the forum I believe this has been brought up but I wanted to make sure my implementation was correct before I give up.

If this is a bug and you have a suggestion how I can create a container that allows the user to slid the columns and has rows with TextBox, CheckBox and ComboBox’s in it please let me know.

Best;

Steve

Here is the code I have put together so far:

  class ComboButtDrop
    {
        public string Label { get; set; }
        public string Text { get; set; }
        public bool Check { get; set; }
        public string Drop { get; set; }
    }


 public class EtoHelloForm : Eto.Forms.Form
    {
        public EtoHelloForm()
        { 
            var collection = new ObservableCollection<ComboButtDrop>();
		collection.Add(new ComboButtDrop {Label = "Label 01", Text = "Row 1", Check = true, Drop = "Drop 1" });
		collection.Add(new ComboButtDrop {Label = "Label 02", Text = "Row 2", Check = false,Drop = "Drop 2" });

		var grid = new GridView { DataStore = collection };

        grid.Columns.Add(new GridColumn {
            DataCell = new TextBoxCell { Binding = Binding.Property<ComboButtDrop, string>(r => r.Label) },
            HeaderText = "Label",
            Editable = false,
            Resizable = false
        });

        grid.Columns.Add(new GridColumn {
            DataCell = new TextBoxCell { Binding = Binding.Property<ComboButtDrop, string>(r => r.Text) },
            HeaderText = "Text",
            Editable = true,
            Resizable = true
        });

        grid.Columns.Add(new GridColumn {
			DataCell = new CheckBoxCell { Binding = Binding.Property<ComboButtDrop, bool?>(r => r.Check) },
			HeaderText = "Check",
            Editable = true
		});

        grid.Columns.Add(new GridColumn {
            DataCell = new ComboBoxCell("Drop") {DataStore = new List<string>{"Drop 1","Drop 2"}}, 
            HeaderText = "Butt",
            Editable = true
        });

		Content = grid;

        }  
    }