@Override
  public @NotNull ListSelection<? extends DiffRequestProducer> getListSelection() {
    ListSelection<? extends DiffRequestProducer> requests = myRequests;
    if (requests == null) {
      return ListSelection.createSingleton(new DiffRequestProducerWrapper(new LoadingDiffRequest()));
    }
    return requests;
  }
@Override
  public @NotNull ListSelection<? extends DiffRequestProducer> getListSelection()