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