Hey thanks for trying the game! Not sure what you mean by the state change.
But drag and drop the item you want to buy or sell into the singular buy/sell slot under the major inventory. You can also shift click to split item to the next slot if it’s open. To exit the store in the right hand corner click the pirate flag. 🏴☠️
I know not the greatest system ran out of time, the UI could use work. 😁