Angular: Nested scopes

http://angularjs.org/ Model won't be updated in nested scopes.

HTML

<script src="http://code.angularjs.org/angular-1.0.0rc8.js"></script>
<script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<html ng-app>
  <body ng-controller="Controller">
    <div class="form-group row" style="width: 960px" ng-repeat="dimension in formData.Items track by $index">
	<div class="col-md-2 dimension-field">
		<label class="dimension-label">Quantity*</label>
		<input class="form-control form-input" ng-change="OnChangeDimension(dimension.Quantity,$index,'Quantity')" 
		name="quantity" ng-required="true" type="text" ng-model="dimension.Quantity" required>
    </div>
    <div class="col-md-1 col-action add-dimensions">
		<label class="dimension-label"></label>
    <button type="button" ng-click="addNewDimensionOptions(dimension)" title="Duplicate row"></button>
	</div>
	</div>
  </body>

</html>

JavaScript

function Controller($scope) {debugger;
  $scope.formData = {
			Items: [{
				'ContainerSize': '',
				'Packaging': '',
				'Quantity': '',
				'LengthCm': '',
				'WidthCm': '',
				'HeightCm': '',
				'ItemWeightKg': '',
				'TotalWeightKg': ''
			}]
	}
  $scope.addNewDimensionOptions = function (Items) {
		$scope.formData.Items.push(Items);
	}

}