Display widget ID for each widget on the Widgets admin page. [wordpress]

display-widget-ids.php

<?php

/**
 * Display widget ID on Widgets page.
 *
 * Use this to see the IDs of all of your widgets here:
 * WordPress Admin Area > Appearance > Widgets
 *
 * To disable, simply comment out the add_filter() function.
 *
 * @param array $params Information about this widget.
 * @return array The updated $params array.
 */
add_filter( 'dynamic_sidebar_params', 'mycode_dynamic_sidebar_params' );
function mycode_dynamic_sidebar_params( $params ) {
	$params[0]['widget_name'] = '(' . $params[0]['widget_id'] . ') ' . $params[0]['widget_name'];

	return $params;
}