question: @ Override protected EClass findInstantiableCompatible ( EClass eType ) { if ( ! isInstantiatableSubType ( eType , eType ) ) { throw new IllegalStateException ( String . valueOf ( eType ) ) ; } return eType ; }
target:  Later here have to be checked the inheritance hierarchy, too. Currently only the type itself is accepted as type for the cross reference. But the cross reference maybe also typed with a super type of the given type.