This is a modified version of the common.js file in admin panel taken from Open Cart 2.0.3.1
A small fix that will allow you to see in which tab the form validation error occurred.

This mod is intended for use on OpenCart 2.0.3.1 ONLY.
You can simply upload the contents of the archive to the root of your store and override the common.js file.

Probably it will also work on all 2.0.x versions but you have to alter the common.js manually to make sure you don't break anytihng else.

Read more here
http://forum.opencart.com/viewtopic.php?f=110&t=148917&p=574447#p574447