Comment 2 for bug 1277971

StacktraceTop:
 gtk_builder_get_object (builder=0x136bb3f3, name=name@entry=0x7f154ba225c2 "list-treeview") at /build/buildd/gtk+3.0-3.10.7/./gtk/gtkbuilder.c:1448
 get_widget (d=<optimized out>, name=0x7f154ba225c2 "list-treeview") at um-user-panel.c:79
 get_selected_user (d=d@entry=0x3154060) at um-user-panel.c:103
 on_permission_changed (permission=<optimized out>, pspec=<optimized out>, data=0x3154060) at um-user-panel.c:944
 g_closure_invoke (closure=0x316aff0, return_value=0x0, n_param_values=2, param_values=0x7fff857d8910, invocation_hint=0x7fff857d88b0) at /build/buildd/glib2.0-2.39.4/./gobject/gclosure.c:770