'currentStates' property is not observable/bindable

[erichocean]

This works:

  valueBinding: SC.Binding.transform(function() {
    return "State: " + App.statechart.get('currentStates').map(function(state) { return state.get('fullPath'); }).join(', ');
  }).from('App.statechart.firstCurrentState')

This does not:

valueBinding: SC.Binding.transform(function(currentStates) {
  return "State: " + currentStates.map(function(state) { return state.get('fullPath'); }).join(', ');
}).from('App.statechart.currentStates')

I would expect currentStates to be observable for changes the same way that firstCurrentState is.

[erichocean]

By "works", I mean that value updates as the statechart changes state in the first case, but not in the second.