Created attachment 539520 [details] [diff] [review] patch This is not about fixing any real runtime leak, but only to make sure the objects aren't kept alive on shutdown.
There's bug 480191 which suggests more of a cycle collector thing.
Nothing there suggest a cycle collector thing. Peter just says that something should break the cycle, and the patch in this bug does that.
But I'll verify if I can reproduce the leak with the patch.
At least with the patch I can't reproduce the leak.
And actually, since popupmanager is a singleton which will stay alive until shutdown, adding traverse/unlink is effectively the same as releasing member during xpcom-shutdown.