I’m not able to find a solution to this problem..
For some reason when I comment this code away in categories.php the page is loading fine and I can manage my categories, but I guess it is there for a reason and the same code is working fine in edit-tags.php
default:
/*if ( isset($_GET[‘_wp_http_referer’]) && ! empty($_GET[‘_wp_http_referer’]) ) {
wp_redirect( remove_query_arg( array(‘_wp_http_referer’, ‘_wpnonce’), stripslashes($_SERVER[‘REQUEST_URI’]) ) );
exit;
} */