Submitted on behalf of @kevinsu0201.

But at the same time I think I've come accross with another issue. I'm using a mega menu to my product menu. If mouse over my product menu, the product mega menu drops down, and if I move over the mega menu and scroll down, then you see the header and the mega menu hides. But actually I can still click those links on the mega menu, which means the mega menu may have not really hidden, it is just turnning the opacity to zero, that's you can still click the link on the mega menu even if they are invisible. Actually, it is not just the mega menu that causes this issue, but also other dropdown menu will, as long as you keep cursor on the dropdown menu when scrolling down (the header diasppears), the issue occurs. Finally, if you move the cursor away from the mega menu area, this issue disappear. Here is my site to help you understand the issue www.cosiagel.xyz