Rated 5 out of 5 stars

A simple and easy to use set of development tools.
If you need to test your XUL or JavaScript code snippets quickly and easily than this is what you need. I used the XUL and JS tools over 5 months without any problems. I think this add-on is about as bug-free as they come

This review is for a previous version of the add-on (0.3.0.20090502).