Elements that depend on another element must be in the same design option.
Interdependent elements include the following:
If you add the host to a design option, the hosted element is automatically included. If you try to add the hosted element without the host, Revit warns you that the host must also be added.
When you create groups or arrays, selected elements must be in the active option. If no design option is active, they must be in the main model.
If you add elements to a group, the elements must be in the same design option as the group.