FULL PRODUCT VERSION :
<build 1.6.0-rc-b94, mixed mode, sharing>

ADDITIONAL OS VERSION INFORMATION :
Windows XP - Professional - Version 2002 Service Pack 2

EXTRA RELEVANT SYSTEM CONFIGURATION :
Laptop IBM T42P

A DESCRIPTION OF THE PROBLEM :
I use a jEditorPane to display some RTF text, no problem at all since the JDK 1.3 until JDK 1.5. But when I try to display some saved documents with Mustang as JDK, it seems that the height of each line has been increased. The consequence of this change is that a text cannot appear completely anymore (I don���t use any jScrollPane, in fact the size of the editorPane is fixed in advance definitively). After analyzing the values returned by some methods provided within the class BoxView, I���ve noticed that the height of the spans has been increased as compared to the values returned before.

for example:

Font used: Arial size 11
Jdk 1.5 :  Span = 14
Mustang: Span =15

Font used: Arial size 16

Jdk 1.5 :  Span = 19
Mustang: Span =21


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Put a jEdtorPane into a frame and launch this simple application under the jdk1.5 and after the latest release of mustang. Compare directly the result on the screen. Try to enter a text composed of several lines (Arial font)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
By using the jdk 1.5 or previous the text takes less height space than using mustang

---------- BEGIN SOURCE ----------

main class: test.java
*************************************

package editor;

import java.awt.Toolkit;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.Dimension;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2006</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class test {
    boolean packFrame = false;

    /**
     * Construct and show the application.
     */
    public test() {
        Frame1 frame = new Frame1();
        // Validate frames that have preset sizes
        // Pack frames that have useful preferred size info, e.g. from
their layout
        if (packFrame) {
            frame.pack();
        } else {
            frame.validate();
        }

        // Center the window
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        Dimension frameSize = frame.getSize();
        if (frameSize.height > screenSize.height) {
            frameSize.height = screenSize.height;
        }
        if (frameSize.width > screenSize.width) {
            frameSize.width = screenSize.width;
        }
        frame.setLocation((screenSize.width - frameSize.width) / 2,
                          (screenSize.height - frameSize.height) / 2);
        frame.setVisible(true);
    }

    /**
     * Application entry point.
     *
     * @param args String[]
     */
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.

getSystemLookAndFeelClassName());
                } catch (Exception exception) {
                    exception.printStackTrace();
                }

                new test();
            }
        });
    }
}


*************************************

Second classe Frame1:

*************************************

package editor;

import java.awt.BorderLayout;
import java.awt.Dimension;

import javax.swing.*;
import javax.swing.text.*;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2006</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class Frame1 extends JFrame {
    JPanel contentPane;
    BorderLayout borderLayout1 = new BorderLayout();
    JTextPane editor;
    String text="The Caterpillar and Alice looked at each other for some
time in silence:  at last the Caterpillar took the hookah out of its mouth,
and addressed her in a languid, sleepy voice.";

    public Frame1() {
        try {
            setDefaultCloseOperation(EXIT_ON_CLOSE);
            jbInit();
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }

    /**
     * Component initialization.
     *
     * @throws java.lang.Exception
     */
    private void jbInit() throws Exception {
        contentPane = (JPanel) getContentPane();
        contentPane.setLayout(null);
        setSize(new Dimension(400, 300));
        setTitle("Frame Title");
        editor = new JTextPane();

        editor.setBounds(10,10,150,150);
        contentPane.add(editor);

        MutableAttributeSet attr = new SimpleAttributeSet();
        StyleConstants.setFontFamily(attr, "Arial");
        StyleConstants.setFontSize(attr, 11);
        editor.getDocument().insertString(0,text,attr);
    }
}
---------- END SOURCE ----------

REPRODUCIBILITY :
This bug can be reproduced always.

Release Regression From : 5.0u7
The above release value was the last known release where this 
bug was not reproducible. Since then there has been a regression.