Firefox ver. 31.2.0 (sorry, unable to install any later version) + FireBug ver. 2.0.5 (now is the latest). I want to debug my web pages using FireBug extension, but I'm unable to do this. I can't see a FireBug icon anywhere. When I press F12 key, I don't see any FireBug window. I see some other debugging tool instead of FireBug. (May be, it's firefox's own tool). But this tool is not a good replacement for FireBug - it has much less functionality and not convinient in usage. Please, help me to return to FireBug debugging.