Even the most experienced ExtJS developers have errors in their code that sometimes creep into production. As such, I wanted to let you know about something you guys might find useful: a free JavaScript error reporting service called DamnIT (http://damnit.jupiterit.com) that emails you when a JavaScript error occurs in your webpages.
Testing ExtJS components isn't always super easy. It's nearly impossible to build an application that works perfectly across all browsers. DamnIT lets you know immediately when there are problems in your application, so you can fix bugs before they become headaches.