Profile: http://people.mozilla.com/~bgirard/cleopatra/#report=58ab2c71386203f0a5edfca5859ee478db57d7fa I'm not too familiar with this API but this sounds like the kind of step we should be able to bypass on optimized shutdown. It takes about 100ms in my profile and I didn't active firebug on any page.

Here's a recent profile: http://people.mozilla.com/~bgirard/cleopatra/#report=9038e7e8a2517f755e091ff2d7af8cce7185ab28&search=firebug STR: 1) Install firebug 1.9.1 (or the latest possible) 2) Shutdown STR the shutdown profile: 1) Install the latest nightly on either Window or Mac (I tested on Mac) 2) Install the pre-release Gecko Profiler from https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler 3) From the toolbar button on the top left select 'Profile Startup'. The browser will reboot 4) On re-opening two tabs will open, the second will be the shutdown profile and should be similar to the ones I have attached. Filter by 'firebug'

This patch is more aggressive. It silently ignores the call on shutdown on the platform side. This patch doesn't have any observable side effect but that doesn't mean it's safe :).

This seems somewhat dangerous. It means that various callbacks that would not have been invoked will now be called. (Debug mode was on, you shut down without turning it off, so now every script that dies will invoke a stale callback handler that doesn't expect to be called.) Firebug is currently being ported to the new Debugger API, though I don't know the ETA. Given that Firebug users are accustomed to JSD screwing up their performance, I wouldn't think this fix is high enough priority to warrant the risk. (Most developers keep a separate profile for Firebug because of the performance problems, though we've gotten much better semi-recently, at least with non-debugged tabs.)

Mass-closing bugs that relate to legacy versions of add-ons or are otherwise no longer worth tracking. Please comment if you think this bug should be reopened. Sorry for the bugspam. Made you look, though!