Wordpress Disable full-height editor and distraction-free functionality

wordpress-disable-distraction-free.php

<?php

/**
 * Disable Distraction Free Writing Mode and the "Auto Expanding"
 * height of the editor based on a list of post types.
 *
 * @return void
 */
function my_deregister_editor_expand($val, $post_type)
{
    $disabled_post_types = array('custom_post_type', 'page');
    return !in_array($post_type, $disabled_post_types);
}
add_filter('wp_editor_expand', 'my_deregister_editor_expand', 10, 2);