I guess this is easy to solve, but how can I hide mega menu (or Dropline, SplitMenu) under the lightbox popup?
Now, when the lightbox popup is created, the megamenu can be seen underneath the popup and also used through the popup.
I know I should somehow modify the z-index, but don't know how in this case.

I think one solution would be assigning menu just for certain pages, but is that possible..? In default, the menu is showing on every page whether it's published or not from the modules.