As I don't know how to reproduce the bug and it never happened again, I don't think that starting gnome-panel under Valgrind is likely to bring more info :-(
-- [apport] gnome-panel crashed with SIGSEGV in g_signal_emit_valist() https://launchpad.net/bugs/91091 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs