The Debug Bar plugin breaks on Gravity Forms admin pages when No Conflict Mode is turned on. This plugin fixes that issue.

debug-bar-gravity-forms-noconflict.php

<?php
/*
Plugin Name: Debug Bar for Gravity Forms No-Conflict Mode
Plugin URI: http://katz.co
Description: Enable debug bar when Gravity Forms has No Conflict Mode on.
Version: 1.0
Author: Katz Web Services, Inc.
Author URI: http://katz.co
*/
add_filter( 'gform_noconflict_scripts', 'debug_bar_add_gf_noconflict');
add_filter( 'gform_noconflict_styles', 'debug_bar_add_gf_noconflict');

function debug_bar_add_gf_noconflict( $items ) {
	$items[] = 'debug-bar';
	return $items;
}