Your method is complex… Here is simplest function to add BUTTON in TinyMCE: (insert this code in funcitons.php): add_action(‘admin_init’, function() { if (current_user_can(‘edit_posts’) && get_user_option(‘rich_editing’) == ‘true’) { add_filter(‘mce_buttons_2’, ‘register_buttonfirst’); add_filter(‘mce_external_plugins’, ‘add_pluginfirst’); } }); function register_buttonfirst($buttons) { array_push($buttons, “|”, “shortcode_button1” ); return $buttons;} function add_pluginfirst($plugin_array) {$plugin_array[‘MyPuginButtonTag’] = plugin_dir_url( __FILE__ ).’My_js_folder/1_button.php’;return $plugin_array;} add_filter( ‘tiny_mce_version’, ‘my_refresh_mceeee1’); function … Read more