Warning in settings screen

[kalyx]

self::$fields is an array of arrays, but $columns must be an array of strings so we have to take only "label" of fields by using wp_list_pluck

In the example file change the last function to:

public static function _columns( $columns ) {

	$columns = array_merge( $columns, wp_list_pluck( self::$fields, 'label' ) );

	return $columns;
}