Hi
I've meant the exact menu items with category type of a category this articles are in. I have fond no such element, so I have added it and it's workig, but the way You have made the multilanguage makes it difficault to keep all the menu attachements ;/ This could be done a lot easier (I'm talking about multilanguage). In template style You have an option to attache style to language, so in such case attaching style to any menu item won't be neccessary. The way it's done now makes it hard to apply this fix (but just for me since I do not know the menu structure, You should have less problem).
Now I'll explain the fix.
Create new menu item of a type "Category Blog" and select the category, articles in NSP are belong to. That's all, so I hope You can manage that alone. Sorry I cannot help more, but Your site is a little too complex at the moment and I'm afraid I may break something trying ;/ Below couple of screens from the fix: