Top Menu vanishes when using Accordion or Tabs

I have no idea, why this happens, but when adding any ibtana block to my page, then – when filled with information/text – the header menu of my global page vanishes. That shouldnt happen and only happens on desktop version.

Does anybody knows why this happens and how to prevent it from happen?

I can not have a page without a top menu with logo etc, whereas on the next page it is clearly visible. Thats absolutely unprofessional ??

Please help. I tried almost every setting I think, but maybe it is because of the ibtana blocks themselves??

The page I need help with: [log in to see the link]