Fatal error: Uncaught Error: Class "WP_Customize_Panel" not found in C:\xampp\htdocs\canman.ee\wp-includes\customize\class-wp-customize-themes-panel.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\canman.ee\wp-includes\customize\class-wp-customize-themes-panel.php on line 17