admin panel – How to remove “delete” button from category editing page

There is some modification in your code, insted of this class .taxonomy-category tr:hover .row-actions apply css on this class .taxonomy-category .row-actions span.delete, it willl work.

Here is whole code.

add_action('admin_head', 'hide_category_buttons');

function hide_category_buttons() {
   echo '<style>
     .taxonomy-category .row-actions span.delete {
        visibility: hidden;
     }
   </style>';
}