void makeChildren() {
      children = new ArrayList<>();

      List dims = group.getDimensions();
      for (int i = 0; i < dims.size(); i++)
        children.add(new DimensionNode(this, (Dimension) dims.get(i)));

      List vars = group.getVariables();
      for (int i = 0; i < vars.size(); i++)
        children.add(new VariableNode(this, (VariableIF) vars.get(i)));

      List groups = group.getGroups();
      for (int i = 0; i < groups.size(); i++)
        children.add(new GroupNode(this, (Group) groups.get(i)));

      if (debugTree) System.out.println("children=" + group.getFullName() + " ");
    }