Most of you know, but for those that don't, Firefox's Web Developer extension lets you edit CSS live on the page and any changes you make reflect on the page - very handy for tweaking the global.css file and seeing immediate changes.
Very useful indeed, However every time i've used that part of the extension, it's always crashed on me and I've been afraid of trying to use it ever since. It's good if it works for you though.
If you can use it, by all means do so. For some reason though it just requires more than what the browser is sometimes capable of especially with humongous CSS files. It can render them fine, but editing live is rather questionable when thinking of stability.
lament, win2k, last time i tried it though I had 3/4 less memory so that could have been half the cause. Not a fan of the sidebar though for stuff like that.