keyboard shortcuts not working

[karlsebal]

Keyboard shortcuts are not working unless started with XDG_CURRENT_DESKTOP=XFCE

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: simple-scan 3.28.0-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-74.84-generic 4.15.18
Uname: Linux 4.15.0-74-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
CurrentDesktop: GNOME-Flashback:GNOME
Date: Thu Jan 16 09:26:20 2020
InstallationDate: Installed on 2014-11-13 (1889 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcEnviron:
 TERM=st-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-74-generic root=UUID=5259d8a9-df2c-46ad-b1ca-ef05b5a2f02e ro
SourcePackage: simple-scan
UpgradeStatus: Upgraded to bionic on 2019-04-11 (279 days ago)
dmi.bios.date: 04/10/2013
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1708
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: M5A99X EVO
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1708:bd04/10/2013:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A99XEVO:rvrRev1.xx:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: To be filled by O.E.M.