I think I've pretty much exhausted all the various ways in attempting to configure the persistence configuration for an existing project in which the JPA navigation works sometimes and sometimes not.
This specific case where the class inheriting from a MappedSuperclass results in all the fields being red. The datasource is setup and mapped correctly (or so it seems) and yet it keeps reporting it is unable to resolve a column for example which is clearly there and mapped.
I have made sure the correct provider is set and have attempted to manually as well as import the datasources as well as create the datasource outside and from the persistence window.
Over several versions of IntelliJ I've always had some form of issue it seems with getting these attributes to db mappings working totally correct. I don't think I have ever had a configuration that has worked 100% of the time.