Hopefully this is simple, it's not a new feature but just something to make another work better.
Have a softlock on the player chosen in the player section so the highlighted player remains highlighted. At the moment when other players join or leave the cursor stays in the same position, not on the same player..
eg
players 1,2,3,4,5,6,7,8
Choose player 5 of 8 for effect, player 2 leaves.....Highlighted player is now player 6 of 7, instead of remaining on player 5.
Hope that makes sense