Volume notification popup resizes/moves the full screen application

[Vitaly]

When I playing a game (Steam, Counter-Strike: Global Offensive), and touch multimedia volume controls on keyboard (mute, volume up, volume down), notification popups appears, but when popups is being showed, the game's full screen makes a bit smaller at the same time showing Ubuntu's panel and dock (showing their spaces, but not drawing them, just void spaces), when notification volume popup hides back, full screen restores. The problem shown only when volume notification popup is showing.

Steam game called Broforce (full screen)(this game has Unity3d engine), when I change volume, frequently it hangs the game (just before showing notification popup), and whole computer (music still plays), having to restart the PC, because it doesn't respond to Alt+f4, and sometimes doesn't respond to Alt+Tab. I had hangs problems with that game in KDE5/Plasma, but I never had problems in Xfce4.

------------------------------------UPDATE 1---------------------
Now, I put the dock at bottom of the screen (I did not activate autohide), and I don't get dock space showing problem in full screen anymore (top/upside panel still remains showing void space in full screen), so getting the dock at the botton fixes dock showing void panel in full screen applications. Now when I change volume/mute, and while volume notification is showing, I see only void panel space in full screen applications. And when I receive Telegram notifications, happens the same as with volume notifications. Really annoying.
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ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7.1
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
Uname: Linux 4.15.0-36-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 9 17:17:35 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus: virtualbox, 5.2.10, 4.15.0-36-generic, x86_64: installed
ExtraDebuggingInterest: I just need to know a workaround
GraphicsCard:
 NVIDIA Corporation GK104 [GeForce GTX 770] [10de:1184] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. GK104 [GeForce GTX 770] [1043:8481]
InstallationDate: Installed on 2018-10-08 (0 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
MachineType: System manufacturer System Product Name
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-36-generic root=UUID=1030fdb0-f3d8-4f87-b803-39c90775b155 ro quiet splash vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/21/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2501
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: P8Z77-V LX
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2501:bd07/21/2014:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnP8Z77-VLX:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.5-0ubuntu0~18.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.5-0ubuntu0~18.04.1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2

[Daniel van Vugt (vanvugt)]

Sounds related to bug 1725649, but that's closed. I think I've heard of another similar Nvidia bug, somewhere.

[Vitaly (vita-cell)]

Daniel my problem starts by a different way (had no problems with Alt+Tab, maybe because I play different games), but I have the same problem with the screen, and yeah it just looks like that https://imgur.com/a/3stwv
In my case the screen restores back to normal when volume popup hides back. It is just annoying when I change volume.

[Vitaly (vita-cell)]

OK, I am still with Ubuntu18.04, installed xubuntu-desktop package, and it solved all bugs. No more in games crashes, no more full screen moving/resizing when changing sound volume, no more volume notifications bugs, and no more PC hanging when changing sound volume in games. Hope someday GNOME improve.