FULL PRODUCT VERSION :
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
When constructing a new JDesktopPane object, its default background colour is set to the Desktop colour on the Windows Palette, when using the Windows Look and Feel. It should be using the Application Background setting instead, as this is the colour for the background of an MDI window frame, and Desktop is the colour for the Windows desktop.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
To compile:
javac test2.java

To run:
(must be under Windows, as this problem is Windows-specific)
java test2

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
an empty 800 x 600 pixel window with a solid background colour set to the
Windows 'Application Background' colour: (grey on the default Windows
Classic/Windows 2000 colour scheme; also grey on the default Windows XP colour
scheme). This is the same background colour that you get when launching Acrobat
Reader with no file loaded, or after launching Microsoft Word and then closing
the default new file.

ACTUAL -
an empty 800 x 600 pixel window with the 'Desktop' colour (blue on default
Windows Classic/Windows 2000 colour scheme; a darker blue on default Windows XP
colour scheme).

Notes:
Can change the actual colours used by Control Panel -> Display -> Appearance ->
Advanced. But the point is the colour is taken from the wrong setting.



REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

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

class test2 {
public static void main(String[] argv) throws Exception {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
JFrame frame = new JFrame("hello");
frame.getContentPane().add(new JDesktopPane());
frame.setSize(800, 600);
frame.show();
}
}

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

CUSTOMER SUBMITTED WORKAROUND :
if (Toolkit.getDefaultToolkit().getDesktopProperty("win.mdi.backgroundColor") != null)
dp.setBackground((Color) Toolkit.getDefaultToolkit().getDesktopProperty("win.mdi.backgroundColor"));