Hi Jason,
You need to make an explicit style on DataRow which sets the ReadOnly property to true, and then apply that style on the ItemContainerStyle of the DetailConfiguration of the details that you do not want the user to modify.
For example:
<Style x:Key="ReadOnlyRow" TargetType="{x:Type xcdg:DataRow}">
<Setter Property="ReadOnly" Value="True" />
</Style>
<xcdg:DataGridControl.DetailConfigurations>
<xcdg:DetailConfiguration RelationName="..." ItemContainerStyle="{StaticResource ReadOnlyRow}" >
Diane Lafontaine
Technical Support / Technical Support Team Lead
Xceed Software Inc.