regression: cannot create new document types in namespace hgge

Log in on demo server
Go to configuration -> hgge namespace
Add a new document type
The dropdown for the "Super type" is empty, I would have expected to be able to select a value
Also, when pressing "next" without selecting a value, an error is thrown
I'm not sure whether it is possible to create a document without a base type, if not, the UI must check against this