Right now unless you are using API scripts the GM is the only person able to move the turn counter to the next turn. This means that the players have tell the GM that they end there turn then the GM has to click on the button to go to the next turn. I think that if a player has control over the token at the top of the tracker then they should be able to end there turn by clicking on the button. The button would then become inactive for that player unless a token that they control is at the top. If the GM decides that the player is taking to long they can click the button on there end. This feature would speed up game play allowing for more things to be done during the game session.