java/awt/event/MouseEvent/EventTimeInFuture/EventTimeInFuture.java test fail with Compilation error, with message that TestDialog duplicate class

because of:
/*
  @test 1.1 07/06/28
  @bug 6451578
  @library ../../../regtesthelpers
  @build Sysout AbstractTest TestDialog Util
  @summary A mouse listener method happens to process mouse events whose time is in the future.
  @author andrei dmitriev : area=awt.event
  @run main EventTimeInFuture
*/

import java.awt.*;
import java.awt.event.*;
import test.java.awt.regtesthelpers.Util;
import test.java.awt.regtesthelpers.AbstractTest;
import test.java.awt.regtesthelpers.Sysout;
In java/awt/regtesthelpers/
we have TestDialog.java with public class TestDialog, also we hava similar final class TestDialog in Sysout.java,
as solution I comment all source for TestDialog class in Sysout.java, after that test compiles.