Thanks Rob, this is exactly I was looking for.

Hi Abs,

I think a better approach would be to attach the XamContextMenu directly to the DiagramNode element instead of the whole XamDiagram control and then in XAML specify what menu items you want shown in the menu.  Your sample has a Style for DiagramNode called familyMemberNodeStyle so you can attach a setter there that creates the XamContextMenu. You can then either specify a Click event handler or a Command.  If you use a command you can bind to your viewmodel by going through the XamContextMenu.PlacementTargetResolved property.  It would look something like this:

<Setter Property="ig:ContextMenuService.Manager">
    <Setter.Value>
        <ig:ContextMenuManager>
            <ig:ContextMenuManager.ContextMenu>
                <!-- need to change the foreground color because DiagramNode uses white foreground
                and this will propagate to the context menu-->
                <ig:XamContextMenu Foreground="Black">
                    <ig:XamMenuItem Header="header 1" Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type ig:XamContextMenu}}, Path=PlacementTargetResolved.DataContext.MyMenuCommand}"/>
                </ig:XamContextMenu>
            </ig:ContextMenuManager.ContextMenu>
        </ig:ContextMenuManager>
    </Setter.Value>
</Setter>

In the above example code, PlacementTargetResolved will be the DiagramNode and DataContext will be the FamilyTreeViewModel class in your sample.  Then inside this view model you can have an ICommand that executes when the context menu item is clicked and perform some logic there.