Comment 2 for bug 858109

StacktraceTop:
 caribou_keyboard_model_on_group_changed (self=0x7fc450072320, group=<optimized out>, variant=<optimized out>, grpid=<optimized out>) at keyboard-model.c:439
 caribou_keyboard_model_constructor (type=<optimized out>, n_construct_properties=<optimized out>, construct_properties=<optimized out>) at keyboard-model.c:648
 g_object_newv (object_type=<optimized out>, n_parameters=1, parameters=<optimized out>) at /build/buildd/glib2.0-2.29.92/./gobject/gobject.c:1493
 gjs_object_instance_constructor (context=0x1ebbeb0, argc=<optimized out>, vp=0x7fc45413f4f8) at gi/object.c:693
 CallJSNative (vp=<optimized out>, argc=<optimized out>, native=<optimized out>, cx=0x1ebbeb0) at jscntxtinlines.h:701