when displaying a ribbon fullsize with lightbox gallery, the submenu items on my menu, created with CSSMW, disappear when hovering over the full sized image, so it isn't possible to choose a menu item.
this page shows a ribbon with fullsize image by default.
choose Gallery -> Wildlife -> Cute Animals to reveal a different gallery with lightbox.
now try choosing Gallery -> Wildlife -> Webassist Images, and as soon as the cursor hovers over wildlife, the submenu disappears.
It only appears to be a problem with galleries with lightbox