What is the difference between manage_edit-post_columns and manage_post_posts_columns? In WP 3.1, manage_edit-{$post_type}_columns has been supplanted by manage_{$post_type}_posts_columns. – manage_edit-post_type_columns in WordPress Codex Helpful Resources https://www.smashingmagazine.com/2013/12/modifying-admin-post-lists-in-wordpress/ https://codex.wordpress.org/Plugin_API/Filter_Reference/manage_edit-post_type_columns https://developer.wordpress.org/reference/hooks/manage_this-screen-id_sortable_columns/