Filtering Not Working on Editable column

[Bryan]

I have a datagrid that contains a column which has an editable drop down list.

I have filtering set to true, but when you place text in the filter box and click "Equal To" or whatever clause, it breaks/errors out

I get Unhandled Exception error.  Its a messing popup window with a bunch of jargon.

 

Anything I need to alter to make this work with that EditTemplate piece in there?

 

Here is the code

 

    <telerik:GridTemplateColumn HeaderText="ConfirmationType" ItemStyle-Width="240px" AllowFiltering="True" ShowSortIcon="True">
                        <ItemTemplate>
                            <%#DataBinder.Eval(Container.DataItem, "ConfirmationType")%>
                        </ItemTemplate>
                        <EditItemTemplate>
                            <telerik:RadComboBox RenderMode="Lightweight" runat="server" ID="RadComboBox1" DataTextField="ConfirmationType" DataValueField="ConfirmationType" DataSourceID="ConfirmationType" SelectedValue='<%#Bind("ConfirmationType") %>'>
                            </telerik:RadComboBox>
                        </EditItemTemplate>
                    </telerik:GridTemplateColumn>