Ember checklist

I will shamelessly copy my SO question:

http://stackoverflow.com/questions/34182028/ember-checklist

What I absolutely don’t get: after

  1. checking a club

  2. uncheck all players

  3. check again the club, players property will have the players’ ids of the club. but it look like checked=(contains player.id players) does not react to it. Although adding some console.log to the helper shows that it will be computed:

There is a jsbin link too: JS Bin - Collaborative JavaScript Debugging.