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\page\component\addon\activate.php:2 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\admin-columns-pro\admin-columns\templates\admin\page\component\addon\activate.php on line 2