The custom scroll bar creates problems with the Device menu.

I have found what is causing problems with the scroll bar;

/* It sets the height of the submenus. */
ul ul.sub-menu {
    max-height: 200px;
	  overflow-y: auto;
	  overflow-x: hidden;
}

This code creates me in the Device submenu an additional space down.
https://postimg.cc/RWVq7snG

As a second side effect, the submenus on the right do not open.
https://postimg.cc/G9K44n49

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