[canuckistani]

Firebug takes over f12 from Devtools.

Ed: you should try ( and provide feedback to ) Firebug 3, they're dong exactly what you described - implementing Firebug UX on top of Firefox Devtools:

https://github.com/firebug/firebug.next

[EdSharkey]

I tried it early on, but it was unusable. I should really give it another go, yeah.