FULL PRODUCT VERSION :
java version "1.6.0_10-beta"
Java(TM) SE Runtime Environment (build 1.6.0_10-beta-b14)
Java HotSpot(TM) Client VM (build 11.0-b11, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Windows Vista, Windows XP

A DESCRIPTION OF THE PROBLEM :
Configured tree icons won't appear. The following keys are default properties and can be used to set default tree icons:
"Tree.leafIcon"
"Tree.openIcon"
"Tree.closedIcon"

When the keys are configured within a Synth XML file, the icons won't appear - see test case.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See test case. If you're using a different package don't forget to modify the synth configuration ( " <object id=\"treeIcon\" class=\"test.synth.SynthTreeIconTest$TreeIcon\"/>")

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The red rectangles should appear.
ACTUAL -
No red rectangles appear.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
package test.synth;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.io.ByteArrayInputStream;
import java.io.InputStream;

import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JTree;
import javax.swing.UIManager;
import javax.swing.plaf.synth.SynthLookAndFeel;

public class SynthTreeIconTest extends JFrame
{
  private static String synthXml = "<synth>" +
  " <style id=\"all\">" +
  " <font name=\"Dialog\" size=\"12\"/>" +
  " </style>" +
  " <bind style=\"all\" type=\"REGION\" key=\".*\"/>" +
  " <style id=\"tree\">" +
  " <object id=\"treeIcon\" class=\"test.synth.SynthTreeIconTest$TreeIcon\"/>" +
  " <property key=\"Tree.leftChildIndent\" type=\"integer\" value=\"4\"/> " +
  " <property key=\"Tree.rightChildIndent\" type=\"integer\" value=\"12\"/> " +
  " <state>" +
  " <defaultsProperty key=\"Tree.leafIcon\" type=\"idref\" value=\"treeIcon\"/>" +
  " <defaultsProperty key=\"Tree.openIcon\" type=\"idref\" value=\"treeIcon\"/>" +
  " <defaultsProperty key=\"Tree.closedIcon\" type=\"idref\" value=\"treeIcon\"/>" +
  " </state>" +
  " </style>" +
  " <bind style=\"tree\" type=\"region\" key=\"Tree\"/>" +
  "</synth>";
  
  public static void main(String[] args)
  {
    EventQueue.invokeLater(new Runnable(){
      public void run()
      {
        try
        {
          new SynthTreeIconTest();
        }
        catch (Exception e)
        {
          e.printStackTrace();
        }
      }
    });
  }

  public SynthTreeIconTest() throws Exception
  {
    InputStream is = new ByteArrayInputStream(synthXml.getBytes("UTF8"));
    SynthLookAndFeel laf = new SynthLookAndFeel();
    laf.load(is, SynthTreeIconTest.class);
    UIManager.setLookAndFeel(laf);

    JTree tree = new JTree();
    add(tree);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(new Dimension(400, 300));
    setLocationRelativeTo(null);
    setVisible(true);
  }
  
  public static class TreeIcon implements Icon
  {
    public void paintIcon(Component c, Graphics g, int x, int y)
    {
      g.setColor(Color.RED);
      g.drawRect(x, y, getIconWidth()-1, getIconHeight()-1);
    }

    public int getIconWidth()
    {
      return 12;
    }

    public int getIconHeight()
    {
      return 12;
    }
  }
  
}