Syntactical error when Category is superclass of Collective

[JoranL]

When I connect a Collective to a superclass Category I get an error message (see image). But according to https://ontouml.readthedocs.io/en/latest/classes/nonsortals/category/index.html it should be fine. You have explained that this documentation is not up to date, so I just wanted to check if this is the problem here, of maybe something else?