To reproduce: - open 1 firefox window - Open 4 dom inspector windows - From the (windows) taskbar, quickly right-click on the 4 dom inspector items and close them by chosing close Actual result: - a lot of cpu usage (100%-ish, which is I think related to bug 373462) and the last application (=Firefox) closes also. Expected result: Not too much cpu usage, and to leave Firefox open. This regressed between 2007-01-10 and 2007-01-11, so I thin a regression from bug 366393.

I can't reproduce this, Martijn. I have tried my to-day's builds (2007031115) of Mingw and with VC8 (Your Mingw fix, bug 373010, included) . Behaviour is normal with max 15% CPU during the actual closing. Otherwise close to 0%.

Well, I'm definitely experiencing this. I've already had a few cases where Firefox was accidentally closed by this. Note that the cpu pegging usually happens 1-2 seconds after closing the window.

So it sounds like we're crashing, right? It would be good to get a stacktrace if so so that we can investigate if it's exploitable. Otherwise this doesn't sound like a blocker. Marking as non-blocking for now.

No, I don't think it's crashing.

So what's making us "exit" after 4 windows are closed? That sounds very odd.

Ah sorry, this has in fact become worksforme, using: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a4pre) Gecko/20070404 Minefield/3.0a4pre Now closing the dom inspector windows doesn't seem to cause any significant extra cpu usage afterwards.

This has started happening again, it has probably the same new regression range I mentioned in bug 373462, comment 8.

This is worksforme again, with current trunk build. I have to retest again with a profile with more extensions.

Ok, I'm seeing this again with a profile that has a lot of extensions installed (most of them are disabled, though) and has a large history, too. I need a bit more than 4 dom inspector windows open, more like 10 or so, then I just need to follow the steps as mentioned in comment 0. I also see the 100% cpu usage again.

Can you get a stack or a breakpad id?

Like I said before, it's not a crash.