mate-panel crashed with signal 7 in g_hash_table_foreach()

[Donal P. O'Sullivan]

I'm a newbie.
I have no idea what the problem is.
I saw 'an error message' and I'm reporting it.
Everything seems to be OK,
I did not notice anything wrong.
everything continued as normal, except for the error message!
sorry that I can not give you any Tech. info..
Kindest regards.
"This is a superb Distro." 99.9999%,
The 0.0001% = think about "Num Lock" option.

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: mate-panel 1.12.2-1
ProcVersionSignature: Ubuntu 4.4.0-14.30-generic 4.4.5
Uname: Linux 4.4.0-14-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CurrentDesktop: MATE
Date: Mon Mar 21 04:23:37 2016
ExecutablePath: /usr/bin/mate-panel
InstallationDate: Installed on 2016-03-20 (0 days ago)
InstallationMedia: Ubuntu-MATE 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160224)
ProcCmdline: mate-panel
ProcEnviron:
 LANGUAGE=en_IE:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IE.UTF-8
 SHELL=/bin/bash
Signal: 7
SourcePackage: mate-panel
StacktraceTop:
 ?? () from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
 g_hash_table_foreach () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
 gtk_rc_reset_styles () from /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
 g_closure_invoke () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
Title: mate-panel crashed with signal 7 in g_hash_table_foreach()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
XsessionErrors:
 mate-session[1218]: WARNING: Unable to find provider '' of required component 'dock'
 (mate-panel:1471): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1544646, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.