private static ClassIndex getClassIndex(@NotNull DefaultMutableTreeNode node) {
      if (node instanceof UsageNode) return ClassIndex.USAGE;
      if (node instanceof GroupNode) return ClassIndex.GROUP;
      if (node instanceof UsageTargetNode) return ClassIndex.USAGE_TARGET;
      return ClassIndex.UNKNOWN;
    }
private static ClassIndex getClassIndex(@NotNull DefaultMutableTreeNode node)