Increase slots of chest when you open the addWindow obs > i dont speak english eee + or - speak english i from brazil hahaha
You cannot do it currently. There's no way for it. It's possible on MCPC though, I believe that's what lead you to question that.
Cancel inventory open event, copy inventory items to your own Custom inventory with more slots, then send that to the client instead
You can use 2 chest joining them to create a DoubleInventory Code: if($chest instanceof Chest and $tile instanceof Chest){ $chest->pairWith($tile); $tile->pairWith($chest); }