Be sure to explore the ACTIONS buttons on the message screen.
We have added more controls to the ACTIONS screens. Especially in the area of switching puzzles.
One new feature allows either party to delete the TRADE puzzle (the lower puzzle when two are in a message). This is important for cases when someone wants to trade but then the other person discovers they no longer have the puzzle in question. Or if the puzzle is damaged. As long as it hasn't been shipped, it can be removed. The person in the top position can also manually add a puzzle to the bottom (trade) position if they are the one that would be shipping out that trade.
It's ok if that all sounds confusing. Just play around and explore. Not everyone needs all these features. But a few people have needed them so they have been added.