As per g_type_ensure's documentation it is incorrect to mark _get_type functions with G_GNUC_CONST since they have side-effects on their first run. See https://gitlab.gnome.org/GNOME/glib/-/merge_requests/5223 for more details. Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/819>
Add the common shortcut as per: https://developer.gnome.org/hig/reference/keyboard.html#basic-shortcuts