Fatal error: Uncaught Error: Using $this when not in object context in C:\xampp\htdocs\wp-content\plugins\admin-columns-pro\admin-columns\templates\admin\menu.php:9 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\admin-columns-pro\admin-columns\templates\admin\menu.php on line 9