FULL PRODUCT VERSION :
java version " 1.7.0_21 "
Java(TM) SE Runtime Environment (build 1.7.0_21-b12)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Mac OS X 10.8.3 Build version: 12D78
Darwin Kernel Version 12.3.0: Sun Jan 6 22:37:10 PST 2013; root:xnu-2050.22.13~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
In an application with multiple JFrames visible if a modal dialog is created with an owner that is under another JFrame, when the modal dialog is set as visible it is also displayed under the non-owner JFrame.

The provided example works as expected in the following environments:
    - Mac OS X 10.8.4 with Java 1.6.0_45
    - Windows 7 with Java 1.6.0_45
    - Windows 7 with Java 1.7.0_21

The behaviour is different in:
    - Mac OS X 10.8.4 with Java 1.7.0_21


REGRESSION. Last worked in version 6u45

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create two JFrames, " main " and " secondary "
2. Set the " main " JFrame visible, followed by the " secondary "
3. Create a modal JDialog with the " main " JFrame as the owner
4. Make the new JDialog visible

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The owner JFrame is displayed " on top " of the secondary JFrame and the modal dialog on top of it's owner
ACTUAL -
The modal dialog is displayed behind the secondary JFrame

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class FrameTester {

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
final JFrame frame1 = new JFrame( " Main Frame " );
frame1.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame1.setSize(300, 300);
frame1.setVisible(true);

JFrame frame2 = new JFrame( " Second Frame " );
frame2.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame2.setSize(300, 300);
frame2.setVisible(true);

Timer timer = new Timer(5000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
JDialog dialog = new JDialog(frame1, " Dialog " , true);
dialog.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
dialog.setSize(100, 100);
dialog.setVisible(true);
}
});
timer.setRepeats(false);
timer.start();
}
});
}
}

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

CUSTOMER SUBMITTED WORKAROUND :
When the dialog is set to visible, call the toFront method on the parent JFrame.