When I log on to my Gmail today, I received an error bounded by a red box that says “Firebug is known to make Gmail slow unless it is configured correctly”. I didn’t know that!
And as always, Gmail is nice enough to provide a simple workaround.
Firebug is an excellent add-on normally used by web developers so most people will not see this warning at all.
By the way did you notice that there’s a very big improvement in Gmail in terms of UI and also speed?