J2SE Version (please include all output from java -version flag):
 java version "1.6.0-ea"
  Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b47)
  Java HotSpot(TM) Client VM (build 1.6.0-ea-b47, mixed mode, sharing)

Does this problem occur on J2SE 1.4.x or 5.0.x ? Yes / No (pick one)
  Yes

Operating System Configuration Information (be specific):
  Microsoft Windows 2000 [Version 5.00.2195]

Hardware Configuration Information (be specific):
  Pentium 4

Bug Description:
 Extended Modifiers on Mouse Events are wrong

Following the steps produces the following Mouse Events:
java.awt.event.MouseEvent[MOUSE_ENTERED,(450,343),button=0,clickCount=0]
on Test$2[...]
java.awt.event.MouseEvent[MOUSE_PRESSED,(329,251),button=1,modifiers=Button1,extModifiers=Button1,clickCount=1]
on Test$2[...]
java.awt.event.MouseEvent[MOUSE_RELEASED,(329,251),button=1,modifiers=Button1,clickCount=1]
on Test$2[...]
java.awt.event.MouseEvent[MOUSE_EXITED,(329,251),button=1,modifiers=Button1,extModifiers=Button1,clickCount=1]
on Test$2[...]
java.awt.event.MouseEvent[MOUSE_ENTERED,(329,251),button=1,modifiers=Button1,extModifiers=Button1,clickCount=1]
on null.glassPane

The extended modifiers of the last 2 mouse events (after the Mouse
Button was Released) claim that the Button1 is still down.
Either these 2 events should come before the MOUSE_RELEASED event, or
the extended modifiers should not say that the Button1 is down, either
way something is wrong here.

Steps to Reproduce (be specific):
1) Run the code below
2) Press the Button

import java.awt.event.*;
import static java.lang.System.*;
import static javax.swing.JFrame.*;
import javax.swing.*;

public class Test {
  public static void main(String[] args) {
    final JFrame frame = new JFrame();
    frame.add(new JButton(new AbstractAction("Test") {
      public void actionPerformed(ActionEvent anEvent) {
        frame.getGlassPane().setVisible(true);
      }
    }) {
      public void processMouseEvent(MouseEvent anEvent) {
        out.println(anEvent);
        super.processMouseEvent(anEvent);
      }
    });
    frame.getGlassPane().addMouseListener(new MouseAdapter() {
      public void mouseClicked(MouseEvent anEvent) {
        out.println(anEvent);
      }

      public void mousePressed(MouseEvent anEvent) {
        out.println(anEvent);
      }

      public void mouseReleased(MouseEvent anEvent) {
        out.println(anEvent);
      }

      public void mouseEntered(MouseEvent anEvent) {
        out.println(anEvent);
      }

      public void mouseExited(MouseEvent anEvent) {
        out.println(anEvent);
      }
    });
    frame.setSize(500, 500);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
  }
}