I can see the "built in Firebug" user interface building in front of my eyes. The top bar appears and a good 100-300 msec later the second bar with the tabs draw. Toggle F12 mutliple times, it's slow every time (you'd think it's not necessary to redraw everything and that this window could be cached somewhere?). I'm on 50.1.0 Windows 7 x64

With "Electrolysis" isn't that supposed to run even faster than the Firebug add on ?