Hello, PR,
To enable the mega menu to open on hover in the All Department menu, please navigate to the WordPress Dashboard > Appearance > Menus > All Department > Menu Options > Uncheck the Open Submenu by Click option and save the settings.
For reference, please see here:https://www.veed.io/view/6af3dbba-d9d9-4d44-a9b2-8e20ad1115db?sharingWidget=true&panel=share
Best Regards,
8Theme’s Team