TinyMCE Visual Blocks plugin set Show blocks option for all users

Just add this code to functions.php of your theme and then “View” –> “Show blocks” will always be enabled immediately when the page loads

if( !function_exists('custom_settings_tinymce') ){
  function custom_settings_tinymce($init) {

    $init['visualblocks_default_state'] = true;

    return $init;
  }
  add_filter('tiny_mce_before_init', 'custom_settings_tinymce' );
}