I’d like to recommend a Firefox extension to my fellow web developers. It’s called CSSViewer and I’ve used it for quite a while now.

When activated, CSSViewer snaps to your cursor and displays a box listing several CSS properties that apply to the website element which is hovered. There are similar tools available that help web developers work their CSS, but I like this one very much in terms of usability, it’s very straightforward and only does what it’s supposed to do. However, using a combination of such tools will be most effective, like in my case, I use CSSViewer and the popular Web Developer Toolbar which allows editing of CSS stylesheets with real time preview and gives further information about the nesting of elements.

This extension proved especially useful on several occasions when editing given (generated) code as for example in CMS applications or blogs and when identifying display problems. Maybe it will help you, too!