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

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

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