FULL PRODUCT VERSION :
Java 7u71

ADDITIONAL OS VERSION INFORMATION :
Mac OSX 10.10

A DESCRIPTION OF THE PROBLEM :
If you run the class below on a RETINA MacBook Pro (OSX 10.10) the first time you see the JWindow it's a white circle with NO shadow, but then later when it calls setVisible(false) and setVisible(true) the circle has a shadow when it's made visible again which isn't right...

I can't reproduce on non-retina OSX 10.9 so could be either from retina or 10.10 OSX.

Same behavior for both Java 7u71 and 8u25...

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the TestMacShadow test class included to reproduce.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
JWindow shouldn't have shadow from OS after it reappears.
ACTUAL -
JWindow has shadow from OS after it reappears.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class TestMacShadow {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                final JWindow window = new JWindow() {
                    public void paint(Graphics g) {
                        g.setColor(Color.WHITE);
                        g.fillOval(0, 0, getWidth(), getHeight());
                    }
                };

                window.setBackground(new Color(0, 0, 0, 0));
                window.setLocation(new Point(100, 100));
                window.setSize(new Dimension(300, 300));
                window.setAlwaysOnTop(true);
                window.setVisible(true);

                Timer t = new Timer(2000, new ActionListener() {
                    public void actionPerformed(ActionEvent actionEvent) {
                        window.setVisible(!window.isVisible());
                    }
                });

                t.setRepeats(true);
                t.start();
            }
        });
    }
}
---------- END SOURCE ----------