Custom Menu Drop down will not work - shows subpages all the time

Hello!
I have a problem with Wordpress Custom Menu that show subpages all the time instead of using Drop down.
What can be the problem?
I have deactivated my other plugins.
Can there be a configuration problem somewhere? But there is no options alternative in the Custom Menu settings more than which pages that should be linked.

I submitted my question here because I think it can have to with my theme, Atahualpa.