On my website I am trying to place a horizontal navigation bar from which drop-down menus stretch down when you hover the mouse over the buttons, so that the menu overlays the page content.

I have put the navigation bar on top of all content with the "arrange" function.

It works ok with the text, however, when there is a placeholder with a youtube video on the page, the buttons roll down under the video instead of on top of it.

Is there any way I can fix that?