Change L&F while running SwingSet/ProgressBar test will cause NullPointerExcepti

Note: This problem does not occur with Swing 0.1 and JDK 1.1.2

Swing 0.2
JDK 1.1.2

Steps to reproduce the problem:
1. Run ProgressBar test from the SwingSet demo
2. Click on Start Loading Text button
3. Change L&F from Win95 to Rose
   ==> NullPointerException occurs

Stack trace:

java.lang.NullPointerException
        at com.sun.java.swing.text.JPlainView.lineToRect(JPlainView.java:307)
        at com.sun.java.swing.text.JPlainView.damageLineRange(JPlainView.java:299)
        at com.sun.java.swing.text.JPlainView.updateDamage(JPlainView.java:238)
        at com.sun.java.swing.text.JPlainView.insertUpdate(JPlainView.java:200)
        at com.sun.java.swing.text.JTextUI$JViewFactory.insertUpdate(JTextUI.java:411)
        at com.sun.java.swing.text.JTextUI$JTextView.insertUpdate(JTextUI.java:741)
        at com.sun.java.swing.text.JDocument.externalNotifyInsert(JDocument.java:470)
        at com.sun.java.swing.text.JDocument.insertString(JDocument.java:173)
        at com.sun.java.swing.text.JDocument.insertString(JDocument.java:156)
        at com.sun.java.swing.JTextArea.append(JTextArea.java:183)
        at ProgressPanel$LoadThread.run(ProgressPanel.java:155)