Angular tags directive issue

I am using pretty nice plugin which provides tags input directive for AngularJS.

I'm using the parameter onTagAdding to check tag's value before it will be added to input.

on-tag-adding="{expression}" 

So, as documentation says:

Expression to evaluate that will be invoked before adding a new tag. The new tag is available as $tag. This method must return either true or false. If false, the tag will not be added.

So here is an live example.

$scope.checkTag = function(tag) {
     angular.forEach($scope.forbiddenTags, function(e){
        if (e.text === tag.text) {
            alert('Tag is forbidden')
            return false;
        }
     })

     alert('Execution is continuing');
}

I'm expecting that if entered value matches one for those tags from $scope.forbiddenTags array, then false should be returned and function's execution should be stopped, but it works not like i am expecting =). I have tried just with return but it doesn't work either.

Any help and suggestions will be appreciated! Thanks in advance!

via Chebli Mohamed