public boolean mousewheel(Coord c, int amount) {
        for (Widget wdg = lchild; wdg != null; wdg = wdg.prev) {
            if (!wdg.visible)
                continue;
            Coord cc = xlate(wdg.c, true);
            if (c.isect(cc, (wdg.hsz == null) ? wdg.sz : wdg.hsz)) {
                if (wdg.mousewheel(c.add(cc.inv()), amount)) {
                    return (true);
                }
            }
        }
        return (false);
    }