I've only been working with Joomla for a few months but I've found a couple of tools that have really helped in customizing the excellent extensions I've chosen to include in my website.
(1) Firebug - Great for figuring out what CSS classes and files are being applied to a page. http://getfirebug.com/ (2) Windows Grep - Helps you find particular pieces of code in an extension so you can edit them. http://www.wingrep.com/
I didn't discover these tools until fairly recently and they would have saved me hours in customizing extension. Joomla vets probably have been using Firebug and Windows Grep as a matter of course (or maybe can suggest even better tools?).
Both tools are open source (free) but contributions are welcome to help support further development.
The second tool you mention is neither free nor open source, although grep itself is GNU/GPL and so is both free and open source. There may be other grep tools available for Microsoft platforms that are free and open source and a link to one or more of those would be welcome. Firebug is already mentioned on the Where to find diagnostic tools page. I think it would be a good idea to start a new Where to find development tools page and you could include Eclipse on it for starters. That would be the place to link to a free/open source Windows grep tool too. If there is a GUI version of grep for Linux and/or Apple that would be good to list too. Chris Davenport 04:08, 24 August 2008 (EDT)