public Vector2f preferredLayoutSize(WidgetContainerAbstract parent) {
public Vector2f preferredLayoutSize(WidgetAbstractContainer parent) {
    public Vector2f preferredLayoutSize(WidgetContainerAbstract parent) {        if (parent.isVisible() == false)            return new Vector2f();        int tot = parent.getWidgetCount();        float width = 0;        float height = 0;        for (int i = 0; i < tot; i++) {            Widget w = parent.getWidget(i);            Vector2f l = w.getLocation();            Vector2f size = w.getPreferredSize();            if (width < l.x + size.x)                width = l.x + size.x;            if (height < l.y + size.y)                height = l.y + size.y;        }        Vector2f ret = new Vector2f();        ret.x = width;        ret.y = height;        return ret;    }