PopupMenu::containsAnyActiveItems() has the following description:
Returns true if the menu contains any items that can be used.
That means that a menu that just contains separators and/or section headers, both of which can not actually be used, should return 0. The implementation of this function however, does not take that into account. Seems like a bug, right?
On a sidenote, submenu’s containing just separators/section headers also appear as active, but seems to me those should be greyed out as well. I’m assuming that code also uses containsAnyActiveItems()?