Howto get clicked slot position in the inventory

Plugins Plugin Development
5

Still no luck. SlotPos returns no value.

My code:

    @Listener(order = Order.FIRST)
    public void clickEvent(ClickInventoryEvent event) {
        
        if (event.getTargetInventory().getName().get().contains("Vote Rewards") ) {
            Transaction clickTransaction = event.getTransactions().get(0);
            Slot eventinventory = event.getTransactions().get(0).getSlot() ;
            SlotPos slotpos = eventinventory.getProperty(SlotPos.class, null).get(); // <- line 130 Optional.empty

trace:

java.util.NoSuchElementException: No value present
	at java.util.Optional.get(Optional.java:135) ~[?:1.8.0_111]
	at net.rebelgames.voterewardmenu.VoteRewardMenu.clickEvent(VoteRewardMenu.java:130) ~[VoteRewardMenu.class:?]