Marco Zehe (:MarcoZ) Reporter
	Description • 9 years ago

This bug was filed from the Socorro interface and is 
report bp-cb049468-b956-41f4-bef4-aca802150219.
=============================================================

I got this crash while testing e10s on Windows with NVDA. I was asked to restart Firefox after I disabled an add-on. It first hung, then I got Crash Reporter.

I know the Windows e10s a11y stuff isn't finished yet, but filing this anyway so we can watch for it if it creeps up again during the further course of things.

	Marco Zehe (:MarcoZ) Reporter
	Comment 1 • 9 years ago

More info: If the hang occurs, and I then force-restart NVDA by simply pressing its Ctrl+Alt+N desktop shortcut, the hang is resolved, but the Firefox process lingers dead in Task manager. So if I shutdown NVDA, no crash occurs, the hang is gone, but the Firefox process remains without a window.

	Trevor Saunders (:tbsaunde)
	Comment 2 • 9 years ago

So I think this is just NtUserDestroyWindow hanging for some reason, but I have no clue what that might be.  Or what could possibly cause it to block.

	Jim Mathies [:jimm]
	Comment 3 • 9 years ago

(In reply to Trevor Saunders (:tbsaunde) from comment #2)
> So I think this is just NtUserDestroyWindow hanging for some reason, but I
> have no clue what that might be.  Or what could possibly cause it to block.

Yep, looks right. No idea what would cause this, maybe we got caught in some sort of send message hang with nvda? Do they create / hook up child windows to ours?

	James Teh [:Jamie]
	Comment 4 • 9 years ago

(In reply to Jim Mathies [:jimm] from comment #3)
> maybe we got caught in some
> sort of send message hang with nvda? Do they create / hook up child windows
> to ours?
We don't. We do have a SendMessage hook, but you would see nvdaHelperRemote in the stack if that was being called.

	Jim Mathies [:jimm]
	Comment 5 • 9 years ago

https://crash-stats.mozilla.com/report/list?product=Firefox&signature=shutdownhang+|+NtUserDestroyWindow+|+NtUserDestroyWindow+|+nsWindow%3A%3AClearCachedResources%28%29

No longer visible on crash stats. There was a bad gfx bug related to ClearCachedResources fixed a week ago in bug 1120331, which may be the cause of this.

	David Bolter [:davidb] (NeedInfo me for attention)
	Comment 6 • 8 years ago

Let's reopen if it happens again.