Backend menu not reachable in Joomla 3.1.5

-- url of the page with the problem -- : developement site
-- HikaShop version -- : 2.2.2
-- Joomla version -- : 3.1.5
-- PHP version -- : 5.3.27
-- Browser(s) name and version -- : Chrome
-- Error-message(debug-mod must be tuned on) -- : Error_message

The backend menu of the Hikashop shows very big and is not reachable.
See attachment.

Hi,

www.hikashop.com/support/documentation/5...html#display_general :

Menu position : As you might have already seen, HikaShop does not use the standard joomla menu interface. We decided to do our own interface in order to handle an additional level of menus so that you can easily reach any functionality of the HikaShop backend. Our custom menu is added under the title of the page by default on 2.5 and below but some backend templates have a reduced size for this area, thus hiding the menu. So you have here the possibility to add the HikaShop menu above the main area where you should not have such issues. If you upgrade from 1.5 or 2.5 to 3.0 or above, you will have to turn off that option after the update.