FULL PRODUCT VERSION :
java version "1.5.0_04"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_04-b05)
Java HotSpot(TM) Client VM (build 1.5.0_04-b05, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Linux andromeda.basis.com 2.6.12-1.1398_FC4 #1 Fri Jul 15 00:52:32 EDT 2005 i686 i686 i386 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
BasicScrollBarUI.ArrowButtonListener starts a timer in mousePressed(), and stops it in mouseReleased(). If the frame containing the scrollbar is disabled between the MOUSE_PRESSED and the MOUSE_RELEASED events, the mouseReleased() method is never called. If the frame is then re-enabled, the still-running timer causes it to scroll all the way to the end. The sample program is informative.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Run 'java DisableFrameFromScrollBar'
2. Click on the bottom scroll-button as though intending to move one unit down.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I would expect the scroll bar to remain motionless and the scroll button to be unpressed after the frame is re-enabled.
ACTUAL -
The scrollbar thumb moves all the way to the bottom, and the button remains pressed.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
(None)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.FlowLayout;

import javax.swing.JFrame;
import javax.swing.JScrollBar;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class DisableFrameFromScrollBar
{
     public static void main(String[] args)
    {
        JFrame frame = new JFrame(DisableFrameFromScrollBar.class.getName());
        JScrollBar bar = new JScrollBar();
        
        bar.getModel().addChangeListener(new DisableChangeListener(frame));
        frame.getContentPane().setLayout(new FlowLayout());
        frame.getContentPane().add(bar);
        
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 500);
        
        frame.setVisible(true);
    }

    public static class DisableChangeListener implements ChangeListener
    {
        private final JFrame m_frame;
        private boolean m_done = false;
        
        public DisableChangeListener(JFrame p_frame)
        {
            m_frame = p_frame;
        }

        public void stateChanged(ChangeEvent p_e)
        {
            if (! m_done)
            {
                m_frame.setEnabled(false);
                Thread t = new Thread(new Enabler(m_frame));
                t.start();
                m_done = true;
            }
        }
    }

    public static class Enabler implements Runnable
    {
        private JFrame m_frame;

        Enabler(JFrame p_frame)
        { m_frame = p_frame; }

        public void run()
        {
            try
            {
                Thread.sleep(1000);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
            m_frame.setEnabled(true);
        }
    }
}

---------- END SOURCE ----------