Win32: exception thrown when adding a component for the second time

Name: dsC76792 Date: 02/02/2000

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Run the following test case:
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import java.awt.*;
import java.awt.event.*;

public class Test extends WindowAdapter implements ActionListener {

    final Frame frame = new Frame("Frame");
    final TextField textfield = new TextField("Click the button");
    final Button button = new Button("Click me");

    public Test() {
        button.addActionListener(this);
        frame.setLayout(new FlowLayout());
        frame.add(textfield);
        frame.add(button);
        frame.pack();
        frame.addWindowListener(this);
        frame.setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        textfield.setText("Move mouse over me");
        frame.add(textfield);
        frame.pack();
    }

    public void windowClosing(WindowEvent e) {
        System.exit(0);
    }

    public static void main(String[] args) {
        Test test = new Test();
    }
}
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Click the button. Move the mouse over a text field.
The test will throw multiple identical exceptions:

Exception occurred during event dispatching:
java.lang.NullPointerException: null pData
        at sun.awt.windows.WInputMethod.handleNativeIMEEvent(Native Method)
        at sun.awt.windows.WInputMethod.dispatchEvent(WInputMethod.java:279)
        at sun.awt.im.InputContext.dispatchEvent(InputContext.java:206)
        at sun.awt.im.InputMethodContext.dispatchEvent(InputMethodContext.java:181)
        at java.awt.Component.dispatchEventImpl(Component.java:2533)
        at java.awt.Component.dispatchEvent(Component.java:2503)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:323)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:107)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:97)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:88)

After that the text field doesn't react on user input.
The only way to restore its normal operation is to
tab-traverse to it from the button.

Possible cause is that when the focussed component changes we memorize
a reference to the peer of the heavyweight container nearest to the new
focus owner. The test case causes replacement of the text field's peer
with a new one, since we add the same text field to the same frame twice.

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