Firefox Super Slow opening WordPress, GMail, and other pages with Firebug installed – Solution
I noticed that Firefox starts taking a lot of Memory (real and virtual) on my Mac, 1GB – 1.5GB when opened for a while. That is a part of the problem of it being slow of course, but it really starts getting slow and load pages like it is 1985 when I have Firebug installed and running.
Firebug needs to be running only on the pages you test, but not on every external page you visit e.g. WordPress.com, Gmail.com, etc.
“Deactivating” Firebug will make them much more responsive. Gmail used to tell you right away that Firebug would cause issues. But apparently there are many pages where Firebug would slow your loading time to almost unbearable.
To deactivate Firebug for a specific screen check this mini-post: