Comment 2 for bug 1043072

StacktraceTop:
 gtk_widget_verify_invariants (widget=0x20869e0) at /build/buildd/gtk+3.0-3.5.12/./gtk/gtkwidget.c:8485
 gtk_widget_size_allocate (widget=0x2223000, allocation=allocation@entry=0x7fffb5d474d0) at /build/buildd/gtk+3.0-3.5.12/./gtk/gtkwidget.c:4972
 gtk_menu_bar_size_allocate (widget=<optimized out>, allocation=<optimized out>) at /build/buildd/gtk+3.0-3.5.12/./gtk/gtkmenubar.c:601
 panel_menu_bar_object_size_allocate (widget=0x21b6020, allocation=0x7fffb5d47b10) at panel-menu-bar-object.c:154
 g_closure_invoke (closure=0x1f24c80, return_value=0x0, n_param_values=2, param_values=0x7fffb5d47750, invocation_hint=0x7fffb5d476f0) at /build/buildd/glib2.0-2.33.10/./gobject/gclosure.c:777