This bug was filed from the Socorro interface and is report bp-170e16c2-0877-4cf4-a57b-85ba70171019. ============================================================= This is still showing up in decent volume on Nightly, though it looks like it is from a small number of users.

Any ideas, Emilio?

Yes, I think `parent` is null because the kid is not in the flattened tree. It's likely that these users activated the shadow DOM pref or what not... Maybe. Or maybe some weird XBL interaction? In any case I'm moderately sure this should be fixed by the following patch in bug 1404789: Bug 1404789: Do not assume that we're part of the flattened tree when we get notified in the frame constructor. r=bz

I'm marking this bug as status-firefox57=wontfix because the Beta 57 volume is very low and Emilio's fix for bug 1404789 won't be uplifted to Beta 57. This signature is Nightly 58 content process top crash #21, but it doesn't show up in Beta 57's top 300 content process crashes.

(In reply to Emilio Cobos Álvarez [:emilio] from comment #2) > In any case I'm moderately sure this should be fixed by the following patch > in bug 1404789: It looks like bug 1404789 did fix this crash. There haven't been any NoteDirtyElement crashes since Beta 58.0b4.