Non-adjacent Displays fails with uninformative error

[Joey Eremondi]

System: Ubuntu Cosmic

Package: gnome-control-center:
  Installed: 1:3.30.1-1ubuntu2
  Candidate: 1:3.30.1-1ubuntu2
  Version table:
 *** 1:3.30.1-1ubuntu2 500
        500 http://ca.archive.ubuntu.com/ubuntu cosmic/main amd64 Packages
        100 /var/lib/dpkg/status

Expected: an error message about non-adjacent displays when non-adjacent displays were preventing a resolution change
What happened: a generic error message about "hardware limitations".

When trying to change the resolution of my displays, when multiple displays were connected, it failed with the error "Changes Cannot Be Applied: this could be due to hardware limitations."

However, if I run gnome-control-center from the command line, I get the following, much more helpful output:

(gnome-control-center:7405): display-cc-panel-WARNING **: 10:15:42.267: Config not applicable: GDBus.Error:org.freedesktop.DBus.Error.InvalidArgs: Logical monitors not adjecent

Indeed, moving the displays to be adjacent within the settings app fixed the problem and allowed the resolution to be changed.

The GUI should inform users when non-adjacent displays are preventing a settings change, instead of failing with an uninformative message.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: gnome-control-center 1:3.30.1-1ubuntu2
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 30 10:18:43 2018
InstallationDate: Installed on 2018-10-25 (4 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
SourcePackage: gnome-control-center
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

Thank you for your bug report, that's indeed an annoying user experience. A similar problem is discussed upstream on https://gitlab.gnome.org/GNOME/gnome-control-center/issues/247