FULL PRODUCT VERSION :
java version "1.6.0_10"
Java(TM) SE Runtime Environment (build 1.6.0_10-b33)
Java HotSpot(TM) Client VM (build 11.0-b15, mixed mode, sharing)

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

A DESCRIPTION OF THE PROBLEM :
Using the JDesktopPane with Nimbus LnF and set the DragMode to JDesktopPane.LIVE_DRAG_MODE then then drawing of draged window is very slow. By putting some Components to the Window you will get a slide show and the processor load is at 100%.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Use the example code from the tutorial (http://java.sun.com/docs/books/tutorial/uiswing/components/internalframe.html)
and start it with the Nimbus LnF. Create some internal frames and then drag some of them. During this look at the processor load.

  To enforce this effect put some Components in the internal frames and the slide show begin.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expect the same behavior like the other LnFs like Windows or Ocean -> fast painting.
ACTUAL -
a slide show

REPRODUCIBILITY :
This bug can be reproduced always.

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

import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.JInternalFrame;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.KeyStroke;
import javax.swing.UIManager;

/*
 * InternalFrameDemo.java requires:
 * MyInternalFrame.java
 */
public class InternalFrameDemo extends JFrame
                               implements ActionListener {
    JDesktopPane desktop;

    public InternalFrameDemo() {
        super("InternalFrameDemo");

        //Make the big window be indented 50 pixels from each edge
        //of the screen.
        int inset = 50;
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        setBounds(inset, inset,
                  screenSize.width - inset*2,
                  screenSize.height - inset*2);

        //Set up the GUI.
        desktop = new JDesktopPane(); //a specialized layered pane
        createFrame(); //create first "window"
        setContentPane(desktop);
        setJMenuBar(createMenuBar());

        //Make dragging a little faster but perhaps uglier.
        //desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
        desktop.setDragMode(JDesktopPane.LIVE_DRAG_MODE);
        
    }

    protected JMenuBar createMenuBar() {
        JMenuBar menuBar = new JMenuBar();

        //Set up the lone menu.
        JMenu menu = new JMenu("Document");
        menu.setMnemonic(KeyEvent.VK_D);
        menuBar.add(menu);

        //Set up the first menu item.
        JMenuItem menuItem = new JMenuItem("New");
        menuItem.setMnemonic(KeyEvent.VK_N);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                KeyEvent.VK_N, ActionEvent.ALT_MASK));
        menuItem.setActionCommand("new");
        menuItem.addActionListener(this);
        menu.add(menuItem);

        //Set up the second menu item.
        menuItem = new JMenuItem("Quit");
        menuItem.setMnemonic(KeyEvent.VK_Q);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(
                KeyEvent.VK_Q, ActionEvent.ALT_MASK));
        menuItem.setActionCommand("quit");
        menuItem.addActionListener(this);
        menu.add(menuItem);

        return menuBar;
    }

    //React to menu selections.
    public void actionPerformed(ActionEvent e) {
        if ("new".equals(e.getActionCommand())) { //new
            createFrame();
        } else { //quit
            quit();
        }
    }

    //Create a new internal frame.
    protected void createFrame() {
        MyInternalFrame frame = new MyInternalFrame();
        frame.setVisible(true); //necessary as of 1.3
        desktop.add(frame);
        try {
            frame.setSelected(true);
        } catch (java.beans.PropertyVetoException e) {}
    }

    //Quit the application.
    protected void quit() {
        System.exit(0);
    }

    /**
     * Create the GUI and show it. For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
     try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
//UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

} catch (Exception e) {
e.printStackTrace();
}
    
     //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        InternalFrameDemo frame = new InternalFrameDemo();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Display the window.
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

/* Used by InternalFrameDemo.java. */
public class MyInternalFrame extends JInternalFrame {
    static int openFrameCount = 0;
    static final int xOffset = 30, yOffset = 30;

    public MyInternalFrame() {
        super("Document #" + (++openFrameCount),
              true, //resizable
              true, //closable
              true, //maximizable
              true);//iconifiable

        //...Create the GUI and put it in the window...

        //...Then set the window size or call pack...
        setSize(300,300);

        //Set the window's location.
        setLocation(xOffset*openFrameCount, yOffset*openFrameCount);
    }
}

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