簡単なアプレットを作って実行していたんですが、
appletviewerを右上のXボタンで閉じる際に
以下のようなexceptionメッセージが出る場合があるのですがどうすればよいのでしょうか？
しかも出る場合と出ない場合の両方があってもうお手上げ状態なんです。
どうかご教授下さい。

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: component argument pData
at sun.awt.windows.Win32SurfaceData.initOps(Native Method)
at sun.awt.windows.Win32SurfaceData.<init>(Unknown Source)
at sun.awt.windows.Win32SurfaceData.createData(Unknown Source)
at sun.awt.Win32GraphicsConfig.createSurfaceData(Unknown Source)
at sun.awt.windows.WComponentPeer.replaceSurfaceData(Unknown Source)
at sun.awt.windows.WComponentPeer.replaceSurfaceData(Unknown Source)
at sun.awt.windows.WComponentPeer$2.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)