/* XXX what if (x,y) is within a window's border? */
	/* This iterates over all of our surfaces and attempts to find one under the
	 * cursor. This relies on stack being ordered from top-to-bottom. */

	/* Find the topmost visible client (if any) under the cursor, including
	 * borders. This relies on stack being ordered from top to bottom. */

		/* Skip clients that aren't visible */
		if (!VISIBLEON(c, c->mon))
			continue;
		/*
		 * XDG toplevels may have nested surfaces, such as popup windows
		 * for context menus or tooltips. This function tests if any of
		 * those are underneath the coordinates x and y (in layout
		 * coordinates). If so, it sets the surface pointer to that
		 * wlr_surface and the sx and sy coordinates to the coordinates
		 * relative to that surface's top-left corner.
		 */
		double _sx, _sy;
		struct wlr_surface *_surface = NULL;
		_surface = wlr_xdg_surface_surface_at(c->xdg_surface,
				x - c->geom.x - c->bw, y - c->geom.y - c->bw,
				&_sx, &_sy);
		if (_surface) {
			*sx = _sx;
			*sy = _sy;
			*surface = _surface;

		if (VISIBLEON(c, c->mon) && wlr_box_contains_point(&c->geom, x, y)) {
			/*
			 * XDG toplevels may have nested surfaces, such as popup windows
			 * for context menus or tooltips. This function tests if any of
			 * those are underneath the coordinates x and y (in layout
			 * coordinates). If so, it sets the surface pointer to that
			 * wlr_surface and the sx and sy coordinates to the coordinates
			 * relative to that surface's top-left corner.
			 */
			/* XXX set *surface to xdg_surface->surface instead of
			 * NULL?  what should sx/sy be in that case? */
			*surface = wlr_xdg_surface_surface_at(c->xdg_surface,
					x - c->geom.x - c->bw, y - c->geom.y - c->bw,
					sx, sy);