You could try something like this:
...Binding="{Binding RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type Window}}, Path=DataContext.AllowItemCommand}" ...
You could try something like this:
...Binding="{Binding RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type Window}}, Path=DataContext.AllowItemCommand}" ...