More work for MainGame.mnu

internal/ui/list_box.go

@@ -77,6 +77,7 @@ func (d *Driver) buildListBox(group *menus.Group, up, down, thumb *menus.Record,
 	// mostly self-registered at the moment.
 	widget := &Widget{
 		Children:      []*Widget{upWidget, downWidget},
+		Active:        group.Active, // FIXME: children have their own active state
 		ownPaintables: []paintable{element},
 		ownValueables: []valueable{element},
 	}