Comment 2 for bug 1304187

StacktraceTop:
 gtk_widget_size_allocate_with_baseline (widget=0x0, allocation=allocation@entry=0x7fff0742afe0, baseline=baseline@entry=-1) at /build/buildd/gtk+3.0-3.12.0/./gtk/gtkwidget.c:5481
 gtk_widget_size_allocate (widget=<optimized out>, allocation=allocation@entry=0x7fff0742afe0) at /build/buildd/gtk+3.0-3.12.0/./gtk/gtkwidget.c:5687
 cc_panel_size_allocate (widget=0xe79580, allocation=0x7fff0742b390) at cc-panel.c:180
 g_cclosure_marshal_VOID__BOXEDv (closure=0xc32330, return_value=<optimized out>, instance=<optimized out>, args=<optimized out>, marshal_data=<optimized out>, n_params=<optimized out>, param_types=0xc323a0) at /build/buildd/glib2.0-2.40.0/./gobject/gmarshal.c:1160
 _g_closure_invoke_va (closure=0xc32330, return_value=0x0, instance=0xe79580, args=0x7fff0742b238, n_params=1, param_types=0xc323a0) at /build/buildd/glib2.0-2.40.0/./gobject/gclosure.c:831