REGRESSION: Java cup icon appears in title bar of dialogs

FULL PRODUCT VERSION :
java version "1.6.0-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-ea-b38)
Java HotSpot(TM) Client VM (build 1.6.0-ea-b38, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
When using JOptionPane.showMessageDialog and similar methods, the resultant dialog now has a java cup icon displayed in the title bar. Also noticed this now appears in floating (undocked) toolbars so it could be an issue with JDialog.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Save the following application as Cup.java and compile and run on 1.6, then compare against earlier JRE versions:

public abstract class Cup {
  public static final void main(String[] args) {
    javax.swing.JOptionPane.showMessageDialog(null, "More tea vicar?");
    System.exit(0);
  }
}

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No icon in the title bar.
ACTUAL -
The Java cup icon is displayed.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
See above.
---------- END SOURCE ----------

Release Regression From : 5.0u3
The above release value was the last known release where this
bug was known to work. Since then there has been a regression.
###@###.### 2005-06-03 17:47:23 GMT