gnome-shell crashed with SIGABRT in g_assertion_message()

[Clemens Vermeulen]

Crash upon send message in Mozilla Thunderbird.

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: gnome-shell 3.20.3-1ubuntu1~xenial1 [origin: LP-PPA-gnome3-team-gnome3-staging]
ProcVersionSignature: Ubuntu 4.4.0-34.53-generic 4.4.15
Uname: Linux 4.4.0-34-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CrashCounter: 1
CurrentDesktop: GNOME
Date: Sat Aug 27 18:16:33 2016
DisplayManager: gdm3
ExecutablePath: /usr/bin/gnome-shell
InstallationDate: Installed on 2016-05-05 (114 days ago)
InstallationMedia: Ubuntu-GNOME 16.04 LTS "Xenial Xerus" - Release amd64 (20160421)
ProcCmdline: /usr/bin/gnome-shell
Signal: 6
SourcePackage: gnome-shell
StacktraceTop:
 g_assertion_message () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_assertion_message_expr () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libmutter.so.0
 meta_window_compute_group () from /usr/lib/x86_64-linux-gnu/libmutter.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libmutter.so.0
Title: gnome-shell crashed with SIGABRT in g_assertion_message()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Ubuntu GNOME (ug-bot)]

StacktraceTop:
 g_assertion_message () at /tmp/apport_sandbox_FxQ7wy/lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_assertion_message_expr () at /tmp/apport_sandbox_FxQ7wy/lib/x86_64-linux-gnu/libglib-2.0.so.0
 () at /tmp/apport_sandbox_FxQ7wy/usr/lib/x86_64-linux-gnu/libmutter.so.0
 meta_window_compute_group () at /tmp/apport_sandbox_FxQ7wy/usr/lib/x86_64-linux-gnu/libmutter.so.0
 () at /tmp/apport_sandbox_FxQ7wy/usr/lib/x86_64-linux-gnu/libmutter.so.0