Power-off button tries to close all open windows

[Gioele Barabucci]

Since October or September 2019, whenever I press the poweroff button on my laptop, in addition to receiving the usual "Would you like to... Lock, Restart, Power off" dialog, all open applications ask me if I really want to close them.

The attached photo shows an example of this behavior.

It looks like the power off keystroke is not captured by Unity (or what other program is responsible for the showing the power off dialog) but also broadcast to all applications.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.5+16.04.20190312-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-66.75~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-66-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.20
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Fri Nov 8 08:08:13 2019
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Samsung Electronics Co Ltd 2nd Generation Core Processor Family Integrated Graphics Controller [144d:c0d3]
InstallationDate: Installed on 2017-06-24 (866 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
MachineType: SAMSUNG ELECTRONICS CO., LTD. 900X3C/900X3D/900X3E/900X4C/900X4D
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-66-generic root=UUID=696c5d50-d388-4d33-b14a-babf7a7359df ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/09/2013
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: P07ABK
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: NP900X3D-A03IT
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: FAB1
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvrP07ABK:bd04/09/2013:svnSAMSUNGELECTRONICSCO.,LTD.:pn900X3C/900X3D/900X3E/900X4C/900X4D:pvr0.1:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP900X3D-A03IT:rvrFAB1:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvr0.1:
dmi.product.family: ChiefRiver System
dmi.product.name: 900X3C/900X3D/900X3E/900X4C/900X4D
dmi.product.version: 0.1
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.
version.compiz: compiz 1:0.9.12.3+16.04.20180221-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.91-2~16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.5-0ubuntu0~16.04.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.5-0ubuntu0~16.04.1
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Fri Nov 1 17:46:14 2019
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.19.6-1ubuntu4.1~16.04.2
xserver.video_driver: modeset

[Gioele Barabucci (gioele)]

xev shows the following events after I press the power-off button:

    MappingNotify event, serial 37, synthetic NO, window 0x0,
        request MappingKeyboard, first_keycode 8, count 248

    PropertyNotify event, serial 38, synthetic NO, window 0x4400001,
        atom 0x14a (_NET_WM_STATE), time 175585994, state PropertyNewValue

    PropertyNotify event, serial 38, synthetic NO, window 0x4400001,
        atom 0x14a (_NET_WM_STATE), time 175587075, state PropertyNewValue

    MappingNotify event, serial 38, synthetic NO, window 0x0,
        request MappingKeyboard, first_keycode 8, count 248

    PropertyNotify event, serial 39, synthetic NO, window 0x4400001,
        atom 0x14a (_NET_WM_STATE), time 175588730, state PropertyNewValue