Thank you for this very quick reply

If I quit the game, the 3rd player disappear.
I tried several times to create a 3rd player and play for at least half an hour, but then if I switch to my 1rst or 2nd player and try to go back to the 3rd one, I can't even select it on the list! I try to click on it, but nothing happens; the selection switches from the firts player to the second player, and vice versa.

And if I quit, the next time I play, the 3rd player doesn't appear anymore.

Is there something I can do??