unity-panel-service crashed with SIGSEGV in g_signal_emit()

[sddania]

when the bug appears I try to set the level of the system sound.
the panel will lock for a few second and the menu of the level of the sound didn't have the orange coloured bar.

Description: Ubuntu oneiric (development branch)
Release: 11.10

unity:
  Installato: 4.0.1-0ubuntu3
  Candidato: 4.0.1-0ubuntu3
  Tabella versione:
 *** 4.0.1-0ubuntu3 0
        500 http://it.archive.ubuntu.com/ubuntu/ oneiric/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity-services 4.0.1-0ubuntu3
ProcVersionSignature: Ubuntu 3.0-3.4-generic 3.0.0-rc5
Uname: Linux 3.0-3-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
CrashCounter: 1
Date: Mon Jul 4 22:25:04 2011
EcryptfsInUse: Yes
ExecutablePath: /usr/lib/unity/unity-panel-service
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110704.1)
ProcCmdline: /usr/lib/unity/unity-panel-service
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=it_IT.UTF-8
SegvAnalysis:
 Segfault happened at: 0x7f267641e36e <g_signal_emit+94>: movl $0x18,0x8(%rsp)
 PC (0x7f267641e36e) ok
 source "$0x18" ok
 destination "0x8(%rsp)" (0x7fff2a9b6fd8) not located in a known VMA region (needed writable region)!
 Stack memory exhausted (SP below stack segment)
SegvReason: writing unknown VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 g_signal_emit () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ?? () from /usr/lib/libgtk-3.so.0
 ?? () from /usr/lib/libgtk-3.so.0
 ?? () from /usr/lib/libgtk-3.so.0
 ?? () from /usr/lib/libgtk-3.so.0
Title: unity-panel-service crashed with SIGSEGV in g_signal_emit()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Apport retracing service (apport)]

StacktraceTop:
 g_signal_emit (instance=0x2303a20, signal_id=33, detail=0) at /build/buildd/glib2.0-2.29.8/./gobject/gsignal.c:3043
 gtk_grab_notify_foreach (child=0x2303a20, data=0x7fff2a9b72c0) at /build/buildd/gtk+3.0-3.1.6/./gtk/gtkmain.c:2132
 gtk_box_forall (container=<value optimized out>, include_internals=<value optimized out>, callback=0x7f26771b5220 <gtk_grab_notify_foreach>, callback_data=0x7fff2a9b72c0) at /build/buildd/gtk+3.0-3.1.6/./gtk/gtkbox.c:1838
 gtk_grab_notify_foreach (child=0x2384e40, data=0x7fff2a9b72c0) at /build/buildd/gtk+3.0-3.1.6/./gtk/gtkmain.c:2100
 gtk_image_menu_item_forall (container=0x219f3c0, include_internals=1, callback=0x7f26771b5220 <gtk_grab_notify_foreach>, callback_data=0x7fff2a9b72c0) at /build/buildd/gtk+3.0-3.1.6/./gtk/gtkimagemenuitem.c:637