@Override
        protected @NotNull ListSelection<ChangeDiffRequestProducer> loadRequestProducers() throws DiffRequestProducerException {
          try {
            Collection<Change> changes = changesLoader.compute();

            Map<Key<?>, Object> changeContext = new HashMap<>(2);
            changeContext.put(DiffUserDataKeysEx.VCS_DIFF_LEFT_CONTENT_TITLE, revNumTitle1);
            changeContext.put(DiffUserDataKeysEx.VCS_DIFF_RIGHT_CONTENT_TITLE, revNumTitle2);

            return ListSelection.createAt(new ArrayList<>(changes), 0)
              .map(change -> ChangeDiffRequestProducer.create(project, change, changeContext));
          }
          catch (VcsException e) {
            throw new DiffRequestProducerException(e);
          }
        }
@Override
        protected @NotNull ListSelection<ChangeDiffRequestProducer> loadRequestProducers()