JInternalFrame iconed, Changing L&F causes NullPointerException on win32

On Win32 Japanese /Kestrel "K" build

When JInternalFrame is iconed or maximized, changing L&F,
NullPointerExeception as below occurs.
Once the Exception occurs, when frame is restored,
it always occurs in changing L&F.


Exception occurred during event dispatching:
java.lang.NullPointerException
at javax.swing.plaf.basic.BasicInternalFrameUI$ComponentHandler.componen
tResized(BasicInternalFrameUI.java:997)
at java.awt.Component.processComponentEvent(Component.java:3472)
at java.awt.Component.processEvent(Component.java:3430)
at java.awt.Container.processEvent(Container.java:1252)
at java.awt.Component.dispatchEventImpl(Component.java:2506)
at java.awt.Container.dispatchEventImpl(Container.java:1301)
at java.awt.Component.dispatchEvent(Component.java:2420)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:302)
at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:10
5)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:95)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:86)



To reproduce,
1)Compile and run the attached programs.
2)Maximize or icon the displayed JinternalFrame.
3)Change L&F.