private static void addParentGroup(@NotNull NotificationParentGroupBean parent,
                                       @NotNull DefaultMutableTreeNode node,
                                       @NotNull Map<NotificationParentGroupBean, List<DefaultMutableTreeNode>> parentChildrenTable) {
      for (NotificationParentGroupBean child : NotificationParentGroup.getChildren(parent)) {
        DefaultMutableTreeNode childNode = new DefaultMutableTreeNode(child);
        addParentGroup(child, childNode, parentChildrenTable);
        node.add(childNode);
      }

      List<DefaultMutableTreeNode> nodes = parentChildrenTable.get(parent);
      if (nodes != null) {
        for (DefaultMutableTreeNode childNode : nodes) {
          node.add(childNode);
        }
      }
    }
private static void addParentGroup(@NotNull NotificationParentGroupBean parent,
                                       @NotNull DefaultMutableTreeNode node,
                                       @NotNull Map<NotificationParentGroupBean, List<DefaultMutableTreeNode>> parentChildrenTable)