Megamenu not showing

Hi there,
thank you for this great product.
I have a large size menu. I resize the wordpress window to 1/4 of my screen. When the menu exceeds the window down level size I can’t use the menu. I was expecting a menu scroll bar.
Also while in mobile mode I can see two menu icons, one for the megamenu(working) and one more( just the icon).

Could you help me please?

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