gdk_event_get_scroll_direction() returns GDK_SCROLL_UP for GDK_SCROLL_SMOOTH
https://gitlab.gnome.org/GNOME/gtk/blob/master/gdk/gdkevents.c#L1239
Well, it returns false
, but also sets direction
to GDK_SCROLL_UP
. This happens in both GTK3 and GTK4.