public void setRows(int rows) {
        if (this.rows != rows) {
            this.rows = rows <= 0 ? 1 : rows;
            // changeLayout();
            layoutChanged = true;
            damagedArea = new BoundaryRectangle(0, 0, width, height);
            if (group != null) {
                group.damage(new BoundaryRectangle(x, y, width, height));
                group.resizeChild(this);
            }
        }
    }