Unable to navigate through JRadioButton/JButton using keyboard mnemonic when components have same mnemonic

OPERATING SYSTEM(S):
Windows XP
Possibly on Linux as well

FULL JDK VERSION(S):

java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) Client VM (build 1.6.0_01-b06, mixed mode)

DESCRIPTION:

Not able to navigate through all the available buttons/radio buttons when more than one button/radio buttons have same mnemonic.

Steps to recreate
-----------------

1. Compile and run the below testcase using the above specified java
2. You can see 3 radio buttons have the same mnemonic keys assigned (ALT+y)
3. Try to navigate through the radio buttons by pressing "ALT+y" combinations
4. The focus always transferred to the last radio button and never navigate through the other radio buttons.

Expected behavior: You should be able to navigate through all the components which supports that mnemonic. For example, when clicking "alt+y" first time, focus should be transferred to first radio button, next time second radio button and so on.

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class JRadioButtonTest extends JFrame{

JRadioButtonTest() {
final int numButtons = 4;
JRadioButton[] radioButtons = new JRadioButton[numButtons];
final ButtonGroup group = new ButtonGroup();

final String defaultMessageCommand = "default";
final String yesNoCommand = "yesno";
final String yeahNahCommand = "yeahnah";
final String yncCommand = "ync";

radioButtons[0] = new JRadioButton("OK (in the L&F's words)");
radioButtons[0].setActionCommand(defaultMessageCommand);
radioButtons[0].setMnemonic(KeyEvent.VK_O);

radioButtons[1] = new JRadioButton("Yes/No (in the L&F's words)");
radioButtons[1].setActionCommand(yesNoCommand);
radioButtons[1].setMnemonic(KeyEvent.VK_Y);

radioButtons[2] = new JRadioButton("Yes/No "
+ "(in the programmer's words)");
radioButtons[2].setActionCommand(yeahNahCommand);
radioButtons[2].setMnemonic(KeyEvent.VK_Y);

radioButtons[3] = new JRadioButton("Yes/No/Cancel "
+ "(in the programmer's words)");
radioButtons[3].setActionCommand(yncCommand);
radioButtons[3].setMnemonic(KeyEvent.VK_Y);

for (int i = 0; i < numButtons; i++) {
group.add(radioButtons[i]);
}

radioButtons[0].setSelected(true);
this.setLayout(new FlowLayout());
for(int i=0;i<numButtons;i++) {
this.getContentPane().add(radioButtons[i]);
}

this.setVisible(true);
this.setSize(800,400);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String arg[]) {
new JRadioButtonTest();
}
}


The same issue can be seen with JButtons, JCheckBox etc.

I think the cause for the problem is how the mnemonics are handled in the KeyboardManager to fireKeyboardAction.