Adding referenced curves by copying and pasteing object id ？

hi，

Firstly I reference some curve from rhino window .Then I want to add one more .  I copy this curve's object id in the properties and paste it into gh's curve persistent data window . However, gh still think that this curve was invalid .

I dont know weather or not gh allow this kind of operation .If yes ,this is a bug I think .If no ,why not?