In addition, the Campaign Details screen now lists all players in your campaign, and if you hover over the player, you have the option to remove them from your Campaign (which will remove them from all in-game lists as well as keep them from re-joining the campaign unless you explicitly re-invite them
I removed some players and they are still showing up in the lists to be able to add them to control tokens. Another strange thing there are duplicates of some of the users in the list as well. If you look at the first screenshot there are only 6 people in the game including myself but in the list there are 8 one that it is just extra (Shawn Hayden Test) and then Alex Hough is duplicated 2 extra times...
Chrome 21.0.1180.60 m, Win 7 Pro