Role Manager: Copy-Paste on an existing role does not work (Exception)

With root, I am trying to define a new "Validator" role (which is basically the same as publisher excepted that it will take care of the first step of the complex workflow rather than on the second step).

So I copy-pasted the publisher role into a newly created "Validator" role. Exception in attachment

BTW: The paste icon is not trivial to use. One would expect to be able to copy and then directly paste a given role. Then the newly created role would be called: "Role_1" or something like that + rename it afterwards. More easy than to have first to create a new role and paste inside the value from another existing role.