Comment 2 for bug 1016671

StacktraceTop:
 g_type_check_instance_cast (type_instance=0xaaaaaaaaaaaaaaaa, iface_type=iface_type@entry=80) at /build/buildd/glib2.0-2.33.2/./gobject/gtype.c:3994
 xfce_appfinder_window_icon_theme_changed (window=0x7f97d199c010) at appfinder-window.c:1452
 _g_closure_invoke_va (closure=0x7f97d1b4acd0, return_value=0x0, instance=0x7f97d1980080, args=0x7fff90759a48, n_params=0, param_types=0x0) at /build/buildd/glib2.0-2.33.2/./gobject/gclosure.c:840
 g_signal_emit_valist (instance=0x7f97d1980080, signal_id=<optimized out>, detail=0, var_args=var_args@entry=0x7fff90759a48) at /build/buildd/glib2.0-2.33.2/./gobject/gsignal.c:3207
 g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at /build/buildd/glib2.0-2.33.2/./gobject/gsignal.c:3352