@Nullable
  private PartialChangeTracker getChangeTrackerFor(@NotNull Change change) {
    if (!myChangeListsEnabled) return null;
    if (myPartialChangeTrackers.isEmpty()) return null;

    if (!myIdx.getChanges().contains(change)) return null;
    ContentRevision revision = change.getAfterRevision();
    if (revision == null) return null;
    return myPartialChangeTrackers.get(revision.getFile());
  }
@Nullable
  private PartialChangeTracker getChangeTrackerFor(@NotNull Change change)