@NotNull
  private static List<CommitNode> collectSelectedCommitNodes(@NotNull List<DefaultMutableTreeNode> selectedNodes) {
    //addAll Commit nodes from selected Repository nodes;
    List<CommitNode> nodes = StreamEx.of(selectedNodes)
      .select(RepositoryNode.class)
      .toFlatList(node -> getChildNodesByType(node, CommitNode.class, true));
    // add all others selected Commit nodes;
    nodes.addAll(StreamEx.of(selectedNodes)
                   .select(CommitNode.class)
                   .filter(node -> !nodes.contains(node))
                   .toList());
    return nodes;
  }
@NotNull
  private static List<CommitNode> collectSelectedCommitNodes(@NotNull List<DefaultMutableTreeNode> selectedNodes)