@NotNull
  protected List<Object> getComboBoxElements() {
    List<Object> result = new SmartList<>();
    BaseToolManager<T> manager = getToolManager();
    result.add(NONE_TOOL);//for empty selection
    for (ToolsGroup<T> group : manager.getGroups()) {
      result.add(group);
      result.addAll(manager.getTools(group.getName()));
    }

    return result;
  }
@NotNull
  protected List<Object> getComboBoxElements()