Since the new look/interface came in, I've notice that Possession isn't working as expected.
I play the Possession card, then when my turn ends I see my next hand, not the other players.
I can't play any actions, since I can't click on any of the action cards, but can click the 'End Actions'.
Same with the Buy phase, since I can't see the treasure cards to play, the only option is 'Autoplay Treasures'.
I asked, the change was apparently unintended. What you can do is click on the bar that contain's your opponent's name (and VP etc.). This causes you to "switch seats", so you see and can click on their cards in to play them or do other things. If you need to interact with your own cards (say you force your opponent to play a Militia), you can do the same again and have access to your hand again.
Oh, good to know.
Thanks!