Temporal solution for bug https://github.com/angular/angular.js/issues/2621

gistfile1.txt

'use strict';

angular
	.module('Decorators', [])
	.config(function($provide){
		/**
		 * Change $watchCollection due to bug #2621
		 * https://github.com/angular/angular.js/issues/2621
		 * remove after official fix
		 */
		$provide.decorator('$rootScope', function($delegate, $parse) {

			function isWindow(obj) {
				return obj && obj.document && obj.location && obj.alert && obj.setInterval;
			}

			function isArrayLike(obj) {
				if (obj == null || isWindow(obj)) {
					return false;
				}

				var length = obj.length;

				if (obj.nodeType === 1 && length) {
					return true;
				}

				return angular.isString(obj) || angular.isArray(obj) || length === 0 ||
					typeof length === 'number' && length > 0 && (length - 1) in obj;
			}

			var ScopePrototype = Object.getPrototypeOf($delegate),
				isObject = angular.isObject,
				initWatchVal = angular.noop;

			ScopePrototype.$watchCollection = function(obj, listener) {
				var self = this;
				var oldValue;
				var newValue;
				var changeFlipFlop = 0;
				var objGetter = $parse(obj);
				var internalArray = [];
				var internalObject = {};
				var internalLength = 0;

				// Holds simple value or reference to internalArray or internalObject.
				// The special initial value is used to ensure that the listener is called
				// when the watch is established and that oldValue = newValue.
				var internalValue = initWatchVal;

				function $watchCollectionWatch() {
					var newLength, key, i, changeDetected;

					newValue = objGetter(self);
					oldValue = internalValue;
					changeDetected = 0;

					if (!isObject(newValue)) {
						if (internalValue !== newValue) {
							internalValue = newValue;
							changeDetected++;
						}
					} else if (isArrayLike(newValue)) {
						newLength = newValue.length;
						if (internalValue !== internalArray) {
							// we are transitioning from something which was not an array into array.
							changeDetected++;
						} else {
							if (internalLength !== newLength) {
								// if lengths do not match we need to trigger change notification
								changeDetected++;
							} else {
								// look for item changes
								for (i = 0; i < newLength; i++) {
									if (internalValue[i] !== newValue[i]) {
										changeDetected++;
										break;
									}
								}
							}
						}
						if (changeDetected) {
							// copy the items to array cache
							internalValue = internalArray = [];
							internalValue.length = internalLength = newLength;
							for (i = 0; i < newLength; i++) {
								internalValue[i] = newValue[i];
							}
						}
					} else {
						if (internalValue !== internalObject) {
							// we are transitioning from something which was not an object into object
							changeDetected++;
						} else {
							// look for item changes
							newLength = 0;
							for (key in newValue) {
								if (newValue.hasOwnProperty(key)) {
									newLength++;
									if (! (internalValue.hasOwnProperty(key) &&
										internalValue[key] === newValue[key])) {
										changeDetected++;
										break;
									}
								}
							}
							if (internalLength !== newLength) {
								changeDetected++;
							}
						}
						if (changeDetected) {
							// copy the items to object cache
							internalValue = internalObject = {};
							internalLength = 0;
							for (key in newValue) {
								if (newValue.hasOwnProperty(key)) {
									internalLength++;
									internalValue[key] = newValue[key];
								}
							}
						}
					}

					if (changeDetected) {
						changeFlipFlop = 1 - changeFlipFlop;
						if (oldValue === initWatchVal) {
							oldValue = newValue;
						}
					}

					return changeFlipFlop;
				}

				function $watchCollectionAction() {
					listener(newValue, oldValue, self);
				}

				return this.$watch($watchCollectionWatch, $watchCollectionAction);
			};

			return $delegate;
		});

	});

Thanks a lot. The dependencies are not quite correct injected though. I had to edit line 5, 11 (and 142, 144), see https://gist.github.com/crusy/eb9f785640592b7f582e