return early if couldn't find the popup's parent

dwl.c

@@ -910,7 +910,7 @@ createnotify(struct wl_listener *listener, void *data)
 	if (xdg_surface->role == WLR_XDG_SURFACE_ROLE_POPUP) {
 		struct wlr_box box;
 		int type = toplevel_from_wlr_surface(xdg_surface->surface, &c, &l);
-		if (!xdg_surface->popup->parent)
+		if (!xdg_surface->popup->parent || type < 0)
 			return;
 		xdg_surface->surface->data = wlr_scene_xdg_surface_create(
 				xdg_surface->popup->parent->data, xdg_surface);