EDIT

                    try {

                        getRepo().getSession().clear();

                        TransactionStatus txStatus = getRepo().startTransaction();

                        // create a blocking registration, the new Registration will be persisted

                        UUID taxonNameUUID = event.getEntityUuid();

                        Registration blockingRegistration = getRepo().getRegistrationService().createRegistrationForName(taxonNameUUID);

                        if(context.get(1).getParentView() instanceof TaxonNamePopupEditor && !((TaxonNamePopupEditor)context.get(1).getParentView()).getBean().cdmEntity().isPersited()){

                            // Oha!! The event came from a popup editor and the

                            // first popup in the context is a TaxonNameEditor with un-persisted name

                            // This is a name for a new registration which has not yet been created.

                            // It is necessary to store blocking registrations in the newNameBlockingRegistrations

                            newNameBlockingRegistrations.add(blockingRegistration);

                            logger.debug("Blocking registration created and memorized");

                        } else {

                            // some new name related somehow to an existing registration

                            TypedEntityReference<Registration> regReference = (TypedEntityReference<Registration>)rootContext.getParentEntity();

                            RegistrationDTO registrationDTO = workingset.getRegistrationDTO(regReference.getUuid()).get();

                            Registration registration = registrationDTO.registration();

                                registration = getRepo().getRegistrationService().load(registration.getUuid());

                                if(registration == null){

                                    throw new NullPointerException("Registration not found for " + regReference + " which has been hold in the rootContext");

                                }

                                registration.getBlockedBy().add(blockingRegistration);

                                getRepo().getRegistrationService().saveOrUpdate(registration);

                                getRepo().commitTransaction(txStatus);

                            logger.debug("Blocking registration created and added to registion");

                    } finally {

                        getRepo().getSession().clear();