@Override
  public int compare(@NotNull VcsRef ref1, @NotNull VcsRef ref2) {
    VcsLogProvider provider1 = myProviders.get(ref1.getRoot());
    VcsLogProvider provider2 = myProviders.get(ref2.getRoot());

    if (provider1 == null) return provider2 == null ? ref1.getName().compareTo(ref2.getName()) : 1;
    if (provider2 == null) return -1;

    if (provider1 == provider2) {
      return provider1.getReferenceManager().getLabelsOrderComparator().compare(ref1, ref2);
    }

    return provider1.getSupportedVcs().getName().compareTo(provider2.getSupportedVcs().getName());
  }
@Override
  public int compare(@NotNull VcsRef ref1, @NotNull VcsRef ref2)