Hi,
I posted this issue on the Protege mailing list here but only realized afterwards there was this Github repository, so my apologies for the cross-posting.
I could use successfully the web version of VOWL with en extremely basic ontology of African wildlife AfricanWildlifeOntology1.owl, however the VOWL plugin in Protege displayed it with numerous incoherences. For example, the VOWL plugin showed "elephant" as a subclass of "plant"...
How to disply such a simple ontology correctly in the VOWL Protege plugin?