this._grabStack[0] is undefined

[Lennart Buit]

As the error doesn't show up in .xsession-errors i was unable to attach a complete bugreport. However, when i use the messageTray, and have a chromium session with flash active (don't know whether it is related, but was something i noticed), my window focus sometimes disappears forcing me to restart the gnome-shell from another tty.

1) Ubuntu 12.10 GNOME-REMIX
2) Gnome-Shell 3.6.2
3) I expected to keep my focus, while somethimes and only when i actively use the messagetray i get a Javascript error (attached at the bottom) and i cannot focus windows anymore.
4) See above

The error i saw:

JS ERROR: !!! Exception was: TypeError: this._grabStack[0] is undefined
JS ERROR: !!! message = '"this._grabStack[0] is undefined"'
JS ERROR: !!! filename = '"/usr/share/gnome-shell/js/ui/grabHelper.js"'
JS ERROR: !!! lineNumber = '329'
...

I tried surrounding the offending javascript line with a null check, but that didn't seem to fix it.

As i could not find logs giving more details about the error, they are not attached, and apport didn't seem to generate any related information. I am willing to provide additional information, and try to contribute to a fix for my bug.

[Jeremy Bícha (jbicha)]

Thank you for reporting this bug to Ubuntu. I apologize that we are not always to respond to bug reports promptly. Ubuntu 12.10 reached End of Life in 2014. See this document for currently supported Ubuntu releases: https://wiki.ubuntu.com/Releases

Please upgrade to Ubuntu 16.04 LTS and re-test. If the bug is still reproducible, increase the verbosity of the steps to recreate it so we can try again.

Do feel free to report any other bugs you may find.