boundaryElement bug

[addictional]

When sticky element rich bottom of parent element , half the Sticky div goes down `render() {

return (
  <div className="cart__sidebar">
    <div className="cart__sidebar-holder">
      <Sticky topOffset={80} boundaryElement=".cart__sidebar" hideOnBoundaryHit={false}>
        <div className="basket">
          <header className="basket__header js-toggable-basket">
            <div className="basket__title-box">
              <div className="basket__title">Корзина</div>
              <div className="basket__subtitle">
                {this.props.items.length}{' '}
                {Utils.pluralWord(this.props.items.length, 'товар', 'товара', 'товаров')} в
                корзине
              </div>
            </div>
          </header>
          <div className="basket__body">
            <div className="basket__products">
              {(() => {
                return this.props.items.map((item, index) => {
                  return <Item key={index} {...item} />;
                });
              })()}
            </div>
          </div>
        </div>
      </Sticky>
    </div>
  </div>
);

}`