How do I make my code be able to stack items properly?

Now it's only stacked the next slot, that's empty. Also, all the FontInventoryQuantity objects are displaying that

Looking at the conditions maybe it needs a bit of work, I think some are not needed. Feel free to share the file and I can take a look

And where can I test picking up items ?

Ok I tidied it up a little and got it working, take a look here dropbox.com/scl/fi/11t8l53k64av4tggggihq/game_edited.c3p

Thank you! Now it's finally working.

Hello again now I'm struggling on: when I left click on a item, like a potion, it substract it's amount or, if the amount goes to 0, the item gets destroyed. The problem is: when I add an item again, it's added only on the slot that had the deleted item, so when I get another item, it can't go on front of the last inventory slot

here is the updated code

and the code to delete the item, or substract it's amount

I can imagine a problem but it doesn't sound like what you described. Because you are always adding 1 to the slot ID and then using this as the next empty one then deleting items in the middle won't work so I can see that you need to rework the empty slot ID logic but you said the problem is its always added on the slot of the deleted item ? So is that what you meant that it doesn't find the new empty slot ?

To rework that logic to find the empty one you can rather than add 1 to curslotID, add an event to set curslotID to the first column that has 0 amount... so for each x if no item name at curx,0 then set that x to the curslotID. You can add this to top of the function before the other checks.

I was saying that when I pick up an item, it was added to the empty slot, but when I pick up a different item, it doesn't appear on the next empty slot.

I was saying that when I pick up an item, it was added to the empty slot, but when I pick up a different item, it doesn't appear on the next empty slot.

That was working in the file I shared though right ?

I would expect that to work for the next new item, I guess it breaks for the one after that because it could overwrite the next. If you do the above in my recent post for calculating cur slot ID then it should all come together, there will be no need to set slot ID when you delete the item or add 1 to it, it will just go to the first empty slot each time (assuming that is how you want it in the game)