>>>Looks like a different problem. What's the ComboBox ItemsSource ?
>>
>>this is the combo's definition:
>>
>>

<ComboBox Grid.Column="1" Grid.RowSpan="1" Margin="0" Name="cboCountries" VerticalAlignment="Center" 
>>DisplayMemberPath="cnt_code" SelectedValuePath="cnt_pk" SelectedValue="{Binding cus_cntfk, Mode=Default}" />
>>

>>
>>and here's the code that sets its itemsource:
>>
>>

this.cboCountries.ItemsSource = this.Country.GetAllEntities();

>
>Hmm. Does 'cnt_code' show up in the list ? If so then it's obviously something strange with 'cnt_pk'

Apparently it is working despite those messages!?