 		 */
 		protected final function registerChild(child:View):void
 		{
+			if (!child) return;
 			if (!_children) _children = new Vector.<View>();
 			child.setViewParams(_screen);
 			_children.push(child);

		 */
		protected final function unregisterChild(child:View):Boolean
		{
			if (!_children) return false;
			var i:int = _children.indexOf(child);
			if (i > -1)
			{

		 */
		protected function disposeChildView(child:View):void
		{
			if (!child) return;
			unregisterChild(child);
			if (contains(child)) removeChild(child);
			child.dispose();
