Flash Builder4.0新建Flex应用程序切换主题出错

<?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" width="100%" height="100%"> <s:layout> <s:BasicLayout/> </s:layout> <fx:Declarations> <!-- 将非可视元素（例如服务、值对象）放在此处 --> </fx:Declarations> <mx:VBox width="99%" height="99%" borderVisible="true" borderStyle="solid" borderColor="#FF0000" paddingBottom="5" paddingLeft="5" paddingRight="5" paddingTop="5"> <mx:HBox width="100%" height="25%" borderVisible="true" borderStyle="solid" borderColor="#00FF00"> </mx:HBox> <mx:HBox width="100%" height="50%" borderVisible="true" borderStyle="solid" borderColor="#0000FF" paddingBottom="5" paddingLeft="5" paddingRight="5" paddingTop="5"> <mx:VBox width="25%" height="100%" borderVisible="true" borderStyle="solid" borderColor="#456745"> </mx:VBox> <mx:VBox width="50%" height="100%" borderVisible="true" borderStyle="solid" borderColor="#ED7867"> </mx:VBox> <mx:VBox width="25%" height="100%" borderVisible="true" borderStyle="solid" borderColor="#123298"> </mx:VBox> </mx:HBox> <mx:HBox width="100%" height="25%" borderVisible="true" borderStyle="solid" borderColor="#006778"> </mx:HBox> </mx:VBox> </s:Application>