toyomedia

Thanks for replying, ManusH.
Unfortunately, it didn’t work for me.

I also tried

function my_allowed_html_tags() {
  define('CUSTOM_TAGS', true);
  global $allowedtags;

  $allowedtags = array(
      'pre' => array(),
      'p' => array(),
      'iframe' => array(
	'title' => array(),
	'line' => array(),
	'width' => array(),
	'height' => array(),
	'frameborder' => array(),
	'src' => array(),
	'webkitallowfullscreen' => array(),
	'mozallowfullscreen' => array(),
	'allowfullscreen' => array(),
			),
  );
}

add_action('init', 'my_allowed_html_tags', 10);

and instead of ‘init’, tried ‘comment_content’ and ‘comment_post’ and ‘$note’.
But shouldn’t ‘init’ be working everywhere?
Anyway, none of them worked..

This is the line that makes customer note work, I guess.
woocommerce/includes/admin/meta-box/class-wc-meta-box-order-notes.php

<?php echo wpautop( wptexturize( wp_kses_post( $note->comment_content ) ) ); ?>

https://davidwalsh.name/wordpress-comment-tags

I tried this

function allow_pres() {
	global $allowedtags;
	$allowedtags['iframe'] = array(
	'class'=>array(),
	'title' => array(),
	'line' => array(),
	'width' => array(),
	'height' => array(),
	'frameborder' => array(),
	'src' => array(),
	'webkitallowfullscreen' => array(),
	'mozallowfullscreen' =>array(),
	'allowfullscreen' => array()
	);
}

add_action('comment_post', 'allow_pres');

I tried ‘comment_content’ and ‘init’ and ‘$note’ instead of ‘comment_post’ but none of them worked.

I got temporary solution..
In /wp-content/wp-includes/kses.php file, I added

'iframe' => array(
	'title' => true,
	'line' => true,
	'width' => true,
	'height' => true,
	'frameborder' => true,
	'src' => true,
	'webkitallowfullscreen' => true,
	'mozallowfullscreen' => true,
	'allowfullscreen' => true,
			),

Is there any way put this function in theme’s function.php instead of doing this in wp core file?