In bug 1520350 I got a patch where the markup of the
<deck> is inserted at the same tick
main.js calls into
In the test
toolkit/mozapps/update/tests/browser/browser_aboutPrefs_fc_check_otherInstance.js, the later script correctly deduces the state of the updater and set the
However, the attribute value gets magically changed to
7 when the test assertion tries to access it.
There is nowhere in JS that could have set the attribute value. The only offender seems to be in
nsDeckFrame::RemoveFrame(). I can't create a Windows build to verify this claim though.
I will workaround this in bug 1520350 but we really shouldn't mutate DOM states from layout ...