gtk_menu_popup_at_rect still has a GdkSurface parameter
void gtk_menu_popup_at_rect (GtkMenu *menu, GdkSurface *rect_surface, const GdkRectangle *rect, GdkGravity rect_anchor, GdkGravity menu_anchor, const GdkEvent *trigger_event);
rect_surface is used as a reference point for
rect is expected to be relative to
Would be nice to get rid of that and replace it with a
GtkWidget * parameter, so
rect would be relative to that widget's origin. Or maybe something else, I'm not exactly sure what would be a good API here or what the backend needs exactly.