pocketmine\tile\Dropper::close PHP Method

    public function close()
    {
        if ($this->closed === false) {
            foreach ($this->getInventory()->getViewers() as $player) {
                $player->removeWindow($this->getInventory());
            }
            foreach ($this->getInventory()->getViewers() as $player) {
                $player->removeWindow($this->getInventory());
            }
            parent::close();
        }
    }