manually closing notification popups causes error messages in journal [messageList.js:504/505]

[Markus Seeber]

closing a notification popup by clicking on the [x] in the notification
popup produces error messages in the journal.

This behavior can be reproduced reliably by calling for example
"notify-send test" in a virtual terminal and closing the
notification popup manually by clicking the [X] button in the
notification popup.

EDIT: log messages were removed from the report and attached as txt file
to preserve line breaks.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.2-0ubuntu0.18.04.1
ProcVersionSignature: Ubuntu 4.15.0-24.26-generic 4.15.18
Uname: Linux 4.15.0-24-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Wed Jul 11 19:19:27 2018
DisplayManager: gdm3
InstallationDate: Installed on 2018-06-26 (15 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Markus Seeber (mseeber)]

Add error messages in plain text since additional line breaks were added by launchpad in the original message.