When a player sends an item that has multiple stacks in his inventory, all items of that type in his inventory are taken from him. Now only the amount that the player has in their hand is sent.

Permission wasn't work properly. This has been fixed.

Items Update is here!!!
Now you can send shulker boxes with contents and items with custom names, lores, enchantments, etc.! You still can't send custom heads and enchanted or written books.
Some minor bugs have also been fixed.