something strange in the menu display

-- HikaShop version -- : 2.6.0
-- Joomla version -- : 3.4.4
-- PHP version -- : 5.4.37
-- Browser(s) name and version -- : Firefox 43.01

hello guys,

i have a problem with the menu. The first attachement shows how the menu should look like. You can see a 2 level horizontal menu . Selecting a menu point on the top gives acess to the menu below where you can select different product categories. when selecting a categorie below the main categorie (in the top) should be stay active (higlightened) - with orange text color and a blue box.

With the German language the menu point"windsurf shop" with its product categories function correctly. Unfortunately with another language it doesn't function like it should - picture 2 shows the difference. the menu point gets deselected if i select a prodct categorie from below.

on the other hand the menu point "sailloft" with its product categories function correctly in italian language but not with the other 2 languages. is there someone who has an clue where the problem is.

thanks so far,
Joman