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:
  JFrame is not in front after call to setVisible(true)
  With the button getting hidden inside a SplitPane, calling 
  frame.setVisible(true) followed by hiding the button leaves the wrong 
  frame in front.

Steps to Reproduce (be specific):
  1) Run the code below
  2) Press the "Show Second Frame and Hide Button" Button

import java.awt.event.*;
import static javax.swing.JFrame.*;
import static javax.swing.JSplitPane.*;
import javax.swing.*;

public class Test {
  public static void main(String[] args) {
    final JButton button = new JButton();
    button.setAction(new AbstractAction("Show Second Frame and Hide Button") {
      public void actionPerformed(ActionEvent anEvent) {
        JFrame frame = new JFrame("Second Frame");
        frame.setSize(500, 500);
        frame.setVisible(true); 
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        button.setVisible(false);
      }
    });
    JFrame frame = new JFrame("First Frame");
    frame.add(new JSplitPane(HORIZONTAL_SPLIT, new JButton("Do Nothing"), button));
    frame.setSize(500, 500);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
  }
}