Can't see dropdowns on web site

[Ed1]

At flightsim.to website, there are tabs near the top of the page labelled: Activity - Liveries - Scenery - Aircraft - Other - Payware - Community. Each of those tabs, when clicked, open a different submenu with a lot of choices for subcategories. With Firefox, the only tab that works properly to display the box with the subcategories is the first one - Activity. All of the others will display the subcategories only when the mouse remains on the tab name, but when the mouse moves down into the subcategory box it immediately closes. This prevents being able to choose any subcategory on those tabs. The behavior with Chrome and Edge is correct - the subcategory box for all tabs remains open while the mouse is moved down into it to select and click on a subcategory.

I noticed that for the Activity tab only, the subcategory box is located immediately below the tab. So, the mouse slides down directly into it. For all of the other tabs, there is some intervening background showing between the tab and the subcategory box, which doesn't remain open long enough for the mouse to get into it.

This seems like some sort of graphics issue with Firefox on this website. It is preventing proper use of that website.

The behavior on Firefox is the same in Firefox safe mode.

Is there any way to correct this?

[Ed1]

Moderator - please delete this double post. I am having trouble with mozillazine login.

[LIMPET235]

Duplicate, locking. Continue the discussion here: http://forums.mozillazine.org/viewtopic ... &t=3085815