gnome-panel crashed with SIGABRT in g_assertion_message()

[Fred]

I switched theme, then I switched theme back.

ProblemType: Crash
DistroRelease: Ubuntu 12.10
Package: gnome-panel 1:3.5.4-0ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-8.8-generic 3.5.0
Uname: Linux 3.5.0-8-generic x86_64
ApportVersion: 2.4-0ubuntu6
Architecture: amd64
Date: Tue Aug 7 23:07:15 2012
ExecutablePath: /usr/bin/gnome-panel
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcCmdline: gnome-panel
Signal: 6
SourcePackage: gnome-panel
StacktraceTop:
 raise () from /lib/x86_64-linux-gnu/libc.so.6
 abort () from /lib/x86_64-linux-gnu/libc.so.6
 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
 gtk_container_propagate_draw () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
Title: gnome-panel crashed with SIGABRT in raise()
UpgradeStatus: Upgraded to quantal on 2012-07-25 (12 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Apport retracing service (apport)]

StacktraceTop:
 g_assertion_message (domain=domain@entry=0x7f8a0992b537 "olor you've chosen.", file=file@entry=0x7f8a09942b30 "unt) > 0", line=line@entry=3335, func=func@entry=0x7f8a09943b70 "set_focus_chain", message=<optimized out>) at /build/buildd/glib2.0-2.33.6/./glib/gtestutils.c:1861
 g_assertion_message_expr (domain=0x7f8a0992b537 "olor you've chosen.", file=0x7f8a09942b30 "unt) > 0", line=3335, func=0x7f8a09943b70 "set_focus_chain", expr=<optimized out>) at /build/buildd/glib2.0-2.33.6/./glib/gtestutils.c:1872
 gtk_container_propagate_draw (container=0x1c63000, child=0x1a553f0, cr=0x1b56400) at /build/buildd/gtk+3.0-3.5.10/./gtk/gtkcontainer.c:3339
 gtk_container_draw (widget=0x863, cr=0x863) at /build/buildd/gtk+3.0-3.5.10/./gtk/gtkcontainer.c:3253
 gtk_menu_item_draw (widget=0x1c63000, cr=0x1b56400) at /build/buildd/gtk+3.0-3.5.10/./gtk/gtkmenuitem.c:1610