8d66fff2aa
So we can style it differently than :hover. We already have a active state for the menu items which includes more than hover. For example, when the keyboard focus moves to a item or we select programatically a item. For this reason we need a style class named active for the meaning we give to it in menu items, and a pseudo class active with the meaning CSS has. https://bugzilla.gnome.org/show_bug.cgi?id=744680