I am using
wp_nav_menu to display my menu
the structure is
Menu1 Menu2 MENU3 +MENU3-sub1 +MENU3-sub2
When I click MENU3, the css style is "actived", but I click MENU3-sub1 or MENU3-sub2, the "actived" status disappeared. How can I hook all MENU3's submenu on MENU3' css? that means if I click +MENU3-sub2, I still have MENU3 "actived".