Research before you whinge Rated 5 out of 5 stars
For those who are too lazy to read previous posts or the release notes on the firebug website -
"Disable always: when the Firebug UI is not active on any page, the debugger is disabled (minimal overhead)"
Firebug is an awesome add-on I use daily for work which makes it the single most useful add-on for me. I'm impressed with how quickly it's been updated (beta I know but at least they're trying) to work with Firefox 3. On it's own that incompatibility would have stopped me from upgrading.