title: Isolated scope pitfall with ng-model dependency
body: <p>Well, since 'improve this doc' button on AngularJS documentation site doesn't work and discussion is now closed, I'd like to ask a question about 'isolated scope pitfall' paragraph of <a href="http://docs.angularjs.org/api/ng.directive%3angModel.NgModelController" rel="nofollow">ngModelController</a>. </p>
  
  <pre><code>&lt;div ng-app="badIsolatedDirective"&gt;
    &lt;input ng-model="someModel"/&gt;
    &lt;div isolate ng-model="someModel"&gt;&lt;/div&gt;
    &lt;div isolate ng-model="$parent.someModel"&gt;&lt;/div&gt;
  &lt;/div&gt;
  
  angular.module('badIsolatedDirective', [])
    .directive('isolate', function() {
      return {
        require: 'ngModel',
        scope: { },
        template: '&lt;input ng-model="innerModel"&gt;',
        link: function(scope, element, attrs, ngModel) {
          scope.$watch('innerModel', function(value) {
            console.log(value);
            ngModel.$setViewValue(value);
          });
        }
      };
  });
  </code></pre>
  
  <p>I expected to see the third input affecting first one (cause we just isolated second input's scope and have no reference to 'someModel' scope value), btw behavior of this example is just stunning: second input affects first, third doesn't affect anything. So the question is: am I loosing the concept or just don't understand it, or there are mistakes (maybe, not mistakes, but just no connection to the topic) in the example code (well, I changed it on <a href="http://plnkr.co/edit/ynqHlkYvajSrZqCWUuCz" rel="nofollow">Plunkr</a> to make it work as I expected).</p>