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Bug 741145 - Sometimes alt+tab stops working until the end of Gnome session
Sometimes alt+tab stops working until the end of Gnome session
Status: RESOLVED DUPLICATE of bug 736527
Product: gnome-shell
Classification: Core
Component: window-management
3.14.x
Other Linux
: Normal normal
: ---
Assigned To: gnome-shell-maint
gnome-shell-maint
Depends on:
Blocks:
 
 
Reported: 2014-12-05 08:13 UTC by Konstantin Mochalov
Modified: 2014-12-10 18:56 UTC
See Also:
GNOME target: ---
GNOME version: ---



Description Konstantin Mochalov 2014-12-05 08:13:39 UTC
Sometimes (I didn't figure out after what event) alt+tab key combination used to switch between windows stops working. It stops switching windows and showing switch popup, doing nothing.

Only restarting Gnome session restores it.

GNOME Shell 3.14.2
Comment 1 Rui Matos 2014-12-05 14:32:56 UTC
Are there any log messages in the journal when this happens?
Comment 2 Konstantin Mochalov 2014-12-05 16:05:58 UTC
Fri 2014-12-05 19:01:27.471005 MSK [s=170968bfdd4e417e871c548e62b61573;i=b711;b=eaef8db96b2f4474ab10d8093c9f5c85;m=75d342aeb;t=5097a3079539d;x=6b24983183d69e8c]
    PRIORITY=6
    _UID=1000
    _GID=1000
    _CAP_EFFECTIVE=0
    _SYSTEMD_OWNER_UID=1000
    _SYSTEMD_SLICE=user-1000.slice
    _MACHINE_ID=13b21463c40744d6bf3187eec7a2d7f2
    _TRANSPORT=stdout
    _EXE=/usr/bin/gnome-session
    SYSLOG_IDENTIFIER=gnome-session
    _COMM=gnome-session
    _CMDLINE=gnome-session
    _HOSTNAME=bullfinch
    _SYSTEMD_CGROUP=/user.slice/user-1000.slice/session-c2.scope
    _SYSTEMD_SESSION=c2
    _SYSTEMD_UNIT=session-c2.scope
    MESSAGE=AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
    _BOOT_ID=eaef8db96b2f4474ab10d8093c9f5c85
    _PID=4136

This message is repeating periodically:

Dec 05 19:01:22 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:01:22 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:01:22 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:01:22 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:01:26 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:01:26 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:01:26 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:01:27 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:01:27 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:01:27 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:03:00 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:03:28 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:03:28 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:03:28 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
Dec 05 19:04:06 bullfinch gnome-session[4136]: AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
Dec 05 19:04:06 bullfinch gnome-session[4136]: AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
Dec 05 19:04:06 bullfinch gnome-session[4136]: AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72


P.S. Discovered that sometimes alt+tab functionality restores to working state without restarting gnome session (maybe after screen lock).
Comment 3 Rui Matos 2014-12-07 14:42:37 UTC
(In reply to comment #2)
> AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
> Dec 05 19:04:06 bullfinch gnome-session[4136]:
> AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
> Dec 05 19:04:06 bullfinch gnome-session[4136]:
> AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72

Can you show us the full log around these? There ought to be more output than this, in particular there should messages like:

%s appears to be running, but doesn't have any windows

They were added in bug 722434 but I'm not completely sure why it was made so that the switcher wouldn't show up at all. It seems like we could just ignore the application that triggers this case and continue showing the switcher with the remaining apps. Florian ?
Comment 4 Florian Müllner 2014-12-07 20:17:43 UTC
(In reply to comment #3)
> They were added in bug 722434 but I'm not completely sure why it was made so
> that the switcher wouldn't show up at all.

"This should never happen, but if it does anyway, let's log() it instead of crashing".
I don't mind dealing more gracefully with this case, but we should still try to fix the underlying bug here (an application is running when it has at least one window open, yet here we have an application we think is running without any windows)
Comment 5 Konstantin Mochalov 2014-12-08 09:00:29 UTC
Seems that it is caused by git-gui application and starts with following message in logs:

Dec 08 11:45:27 bullfinch gnome-session[2537]: (gnome-shell:2623): Gjs-WARNING **: JS ERROR: Error: Git-gui appears to be running, but doesn't have any windows

More log:
https://gist.github.com/kolen/cbd7d4647dc761afa273

Quitting git-gui makes alt+tab work again!

"git gui" does not trigger this immediately, repository selection window that appears first not causes this, but main window causes. Also, list of applications (some sort of dock) in gnome shell shows one git-gui window as many duplicate dock items -- maybe related to this.

Following errors are repeating in log:

(gnome-shell:2623): Gjs-WARNING **: JS ERROR: Error: Git-gui appears to be running, but doesn't have any windows
AppSwitcher<._init@resource:///org/gnome/shell/ui/altTab.js:453
wrapper@resource:///org/gnome/gjs/modules/lang.js:169
_Base.prototype._construct@resource:///org/gnome/gjs/modules/lang.js:110
Class.prototype._construct/newClass@resource:///org/gnome/gjs/modules/lang.js:204
AppSwitcherPopup<._init@resource:///org/gnome/shell/ui/altTab.js:67
wrapper@resource:///org/gnome/gjs/modules/lang.js:169
_Base.prototype._construct@resource:///org/gnome/gjs/modules/lang.js:110
Class.prototype._construct/newClass@resource:///org/gnome/gjs/modules/lang.js:204
WindowManager<._startAppSwitcher@resource:///org/gnome/shell/ui/windowManager.js:1391
wrapper@resource:///org/gnome/gjs/modules/lang.js:169

(gnome-shell:2623): Gjs-WARNING **: JS ERROR: TypeError: this._switcherList is null
SwitcherPopup<._allocate@resource:///org/gnome/shell/ui/switcherPopup.js:96
wrapper@resource:///org/gnome/gjs/modules/lang.js:169
_parent@resource:///org/gnome/gjs/modules/lang.js:131
AppSwitcherPopup<._allocate@resource:///org/gnome/shell/ui/altTab.js:72
wrapper@resource:///org/gnome/gjs/modules/lang.js:169
LayoutManager<._init/<@resource:///org/gnome/shell/ui/layout.js:173
Comment 6 Rui Matos 2014-12-10 18:56:08 UTC
(In reply to comment #4)
> I don't mind dealing more gracefully with this case, but we should still try to
> fix the underlying bug here (an application is running when it has at least one
> window open, yet here we have an application we think is running without any
> windows)

OK, that seems to be bug 736527.

*** This bug has been marked as a duplicate of bug 736527 ***