remove_action from parent theme using child theme functions.php

Well, all I needed to fix the issue was to add the exact same priority to the remove_action and it worked pretty well, thanks to Sally CJ answer add_action( ‘wp_head’, ‘remove_site_hero_sections’); function remove_site_hero_sections() { global $theme_header_layout; remove_action(‘theme_site_header’, array($theme_header_layout, ‘site_hero_sections’), 9999); }

Why nav_menu_css_class doesn’t work with apply_filters?

Because that’s not what apply_filters() does. You’ll even see the usage guide and examples at your link all use add_filter(). Also see the official docs on Filters. Using apply_filters() makes a value filterable. add_filter() is used to filter a filterable value by passing a function that does the filtering. WordPress uses apply_filters(‘nav_menu_css_class’, …, which allows … Read more