Comment 2 for bug 1726286

StacktraceTop:
 g_type_check_instance_cast (type_instance=0x4238317839080030, iface_type=94623820557152) at ../../../../gobject/gtype.c:4052
 font_view_update_scale_factor (self=0x560f533cc2a0) at ../src/font-view.c:521
 g_closure_invoke (closure=0x560f53493530, return_value=0x0, n_param_values=2, param_values=0x7ffd18415ac0, invocation_hint=0x7ffd18415a40) at ../../../../gobject/gclosure.c:804
 signal_emit_unlocked_R (node=node@entry=0x560f530fa140, detail=detail@entry=397, instance=instance@entry=0x560f533cc2a0, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7ffd18415ac0) at ../../../../gobject/gsignal.c:3635
 g_signal_emit_valist (instance=0x560f533cc2a0, signal_id=<optimized out>, detail=397, var_args=var_args@entry=0x7ffd18415c90) at ../../../../gobject/gsignal.c:3391