Superfish Dropline -- want sibling items to remain visible when submenu is selected

Superfish Dropline -- want sibling items to remain visible when submenu is selected

I'm using Superfish in a WordPress installation and can't figure out how to make the submenu-level items remain visible when one of them is selected. It works when a top-level item is selected; all submenus remain visible unless another top-level item is hovered. I think the argument is "pathLevels" but it's not working.