Segmentation fault with Ctrl+Q

Hello

Closing pavucontrol via Ctrl+Q results in a segfault. Closing via Alt+F4 works fine.

pavucontrol version: 4.0

gtkmm version: 3.24.0

(gdb) bt
#0  0x00007ffff7d5b4a5 in Gtk::Main::quit () at /var/tmp/portage/dev-cpp/gtkmm-3.24.0/work/gtkmm-3.24.0/gtk/gtkmm/main.cc:383
#1  0x000055555559b5ca in MainWindow::on_key_press_event () at mainwindow.cc:224
#2  0x00007ffff7dbf131 in Gtk::Widget_Class::key_press_event_callback () at /var/tmp/portage/dev-cpp/gtkmm-3.24.0/work/gtkmm-3.24.0/gtk/gtkmm/widget.cc:4482
#3  0x00007ffff6b7ec15 in _gtk_marshal_BOOLEAN__BOXEDv () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkmarshalers.c:129
#4  0x00007ffff676a18a in g_type_class_meta_marshalv () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/gobject/gclosure.c:1030
#5  0x00007ffff676c0de in _g_closure_invoke_va () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/gobject/gclosure.c:873
#6  0x00007ffff6787af3 in g_signal_emit_valist () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/gobject/gsignal.c:3300
#7  0x00007ffff678880a in g_signal_emit () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/gobject/gsignal.c:3447
#8  0x00007ffff6b2c6bc in gtk_widget_event_internal () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkwidget.c:7744
#9  0x00007ffff6b2e804 in gtk_widget_event () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkwidget.c:7314
#10 0x00007ffff69ebcdf in propagate_event () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkmain.c:2675
#11 0x00007ffff69ed4e6 in gtk_propagate_event () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkmain.c:2719
#12 0x00007ffff69edd13 in gtk_main_do_event () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gtk/gtkmain.c:1915
#13 0x00007ffff5d9bbf5 in _gdk_event_emit () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gdk/gdkevents.c:73
#14 0x00007ffff5dccfa2 in gdk_event_source_dispatch () at /var/tmp/portage/x11-libs/gtk+-3.24.1/work/gtk+-3.24.1/gdk/x11/gdkeventsource.c:367
#15 0x00007ffff6686a0e in g_main_dispatch () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/glib/gmain.c:3182
#16 g_main_context_dispatch () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/glib/gmain.c:3847
#17 0x00007ffff6686c38 in g_main_context_iterate () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/glib/gmain.c:3920
#18 0x00007ffff6686cbc in g_main_context_iteration () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/glib/gmain.c:3981
#19 0x00007ffff56e067d in g_application_run () at /var/tmp/portage/dev-libs/glib-2.58.3/work/glib-2.58.3/gio/gapplication.c:2470
#20 0x00007ffff7676195 in Gio::Application::run () at /var/tmp/portage/dev-cpp/glibmm-2.56.1/work/glibmm-2.56.1/gio/giomm/application.cc:1227
#21 0x00007ffff7d02179 in Gtk::Application::run () at /var/tmp/portage/dev-cpp/gtkmm-3.24.0/work/gtkmm-3.24.0/gtk/gtkmm/application.cc:137
#22 0x0000555555588903 in main () at pavuapplication.cc:182