It is not possible to access the elements of the relationship-tab since the new interface launched.
Character Article
Relationships, Diplomacy and Dictionaries are 3 things not yet ported to the new interface. They are still accessible from the Old version. They will be ported into the new UI slowly.
Ok I was confused, since the article about the release explicitly said that everything got ported.
I guess the article is wrong. :D
Is there a way to default to the old layout for the time being?
I work a lot with relationships and having to do all the extra clicks to get to the old editor is quite annoying.