module ActiveAdmin::BaseController::Menu

def current_menu
  active_admin_config.navigation_menu
end

def set_current_tab
  @current_tab = if current_menu && active_admin_config.belongs_to? && parent?
    parent_item = active_admin_config.belongs_to_config.target.menu_item
    if current_menu.include? parent_item
      parent_item
    else
      active_admin_config.menu_item
    end
  else
    active_admin_config.menu_item
  end
end