private static IMenuBarSubMenu createGroupingSubMenu(ITreeNode <RootNodeType> treeNode, IExplorerPresenter presenter)
        {
            var groupMenu = CreateSubMenu.WithCaption(MenuNames.GroupBy);

            presenter.AvailableClassificationCategories(treeNode)
            .Each(classification => groupMenu.AddItem(
                      CreateMenuButton.WithCaption(classification.ClassificationName)
                      .WithActionCommand(() => presenter.AddToClassificationTree(treeNode, classification.ClassificationName))));

            return(groupMenu);
        }