It is very frustrating that I've spent over two hours building a Brawl deck on my Android type phone to answer a phone call and when returning to the Arena, it reloads and it's as if I did nothing for all that time . You NEED an auto save on deck building. This is not the first time this had happened to me and I actually got so mad the first time it happened that I quit playing the have for about a week and have only now decided to try building a deck again because I must to join the brawl event . Very frustrating!!!!!!!!