1511004 - browser-tabsintitlebar.js causes crash on resume from sleep (Windows 10)

Status: RESOLVED INCOMPLETE

(Firefox :: Untriaged, defect)

Description

[franbarton]

Attachment: Firefox screenshot of unresponsive window showing black area

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0

Steps to reproduce:

Resume Windows 10 from sleep or hibernate


Actual results:

Windows is sometimes very slow to restore session after sleep. On these occasions, after resuming after delay, it appears to be Firefox that is the slowest app to respond. Usually when this happens there is a "Warning: Unresponsive script" (or whatever) message showing. And I have noticed recently that the script in question is often (but not always) chrome://browser/content/browser-tabsintitlebar.js:296 (296 is the number on the most recent error message that I screenshot, but I don't know if it always is.

I usually have lots of tabs open, maybe using up lots of memory. I don't think it's a particular website that is causing the error (it happened just now with a website I haven't knowingly visited before today).

Usually I would click on "Continue" or "Stop script" but recently I have wanted to find out what is happening to cause these problems, so I have clicked "Debug script" instead. However, when I do this, Firefox switches to one of its windows and displays the window now with a wide strip at the bottom that is just black (see attached screenshot). I imagine it is trying to display the Developer Tools interface or something like that? However this interface never succeeds in being rendered, the strip just remains black with no text or anything, and the whole window itself is unresponsive - it cannot be closed by clicking on the close button on the tab or on the window. Other Firefox windows are responsive. I end up needing to kill Firefox using Windows Task Manager and to restart Firefox.


Expected results:

Ideally the "Unresponsive script" situation would not occur in the first place, but if it does happen then the "Debug script" action should work - by doing whatever that action is supposed to do, rather than by showing a black rectangle at the bottom of the viewport in an unresponsive (crashed) browser window.

Comment 1

[franbarton]

Further info:
I just tried using Firefox's own Task Manager (about:performance) to close the crashed tab in question. After closing it once, the tab disappeared from the list before immediately reappearing in the list again. After closing it a second time in Task Manager, the tab did not reappear in the list. But the crashed window is still displayed (and unresponsive) on my screen.

Comment 2

[Daniel_A[:daschilean] [Please contact - [e-mail]]]

I verified this issue on Windows 10 x64 with the latest Firefox beta version 64.0b15 (64-bit) and I cannot reproduce it. 
Can you please test this in safe mode? Here is a link that can help you: https://goo.gl/AR5o9d.
I think it will be a good idea to retest this on the latest Firefox Nightly. Here is a link form where you can download it: https://nightly.mozilla.org. 
If you still have the issue please create a new profile, you have the steps here: https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles?redirectlocale=en-US&redirectslug=Managing-profiles#w_starting-the-profile-manager

Comment 3

[Daniel_A[:daschilean] [Please contact - [e-mail]]]

Hi,
Marking this as Resolved: Incomplete due to the lack of response from the franbarton.
If the issue is still reproducible with the latest Firefox version, feel free to reopen the bug.