Wow! I am impressed. Following a discussion on slashdot I've installed the new 1.0 beta version of Firebug, an extension for web developers. Created by the same author as the classic Dom Inspector, Firebug didn't seem too useful for me until now. The version on the mozilla extensions site is old (0.4), not so featured and to me it seemed to be really buggy. The new version seems to work very good and offers for each area of focus a multitude of information and options that puts it on first place in my toolkit as Plone web developer.