After logging in to twitter typing in the tweet box you sometimes get a new window that opens very briefly and then closes. Only seems to happen for me on Windows 7 (haven't tried mac).
I got a regression range but I have almost zero confidence in it since when I tried to narrow the range using hourlies I got contradictory results. http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cd392793b0c0&tochange=ae74a11a7d98 If someone else wants to try finding the regression range that would be great (especially since we can narrow the range using the hourly archive at http://hourly-archive.localgho.st/hourly-archive2/ since it stores about 2 weeks of hourlies).
I also believe this is Windows 7 only. I've never seen it on XP.
Using this testcase repeatedly triggering the go button I can reproduce much easier. And the problem appears in 3.6 too. I'm going to take a guess that I think what might be happening is that we are not responding quick enough and the Windows desktop composition engine detects that and tries to do something (the new window popping up is some kind of not responding window). And I guess the new window opening pops us out of the not responding state somehow.
Bas, does comment 4 ring any bells or am I off in crazy land?
(In reply to comment #4) > (the new window popping up is some kind of not responding window) Yes, that would be Windows Explorer's "ghost" Not Responding window. I don't know about the ghost window's appearance reviving Firefox, but it doesn't sound implausible.
I think this is just the slow twitter typing.