Product: 6.0 Java RE B96 (1.6.0-rc-b96 mixed mode)
Platform: windows-amd64 (I could not repro the problem on win-i386 platform)

Steps:
=====
It is pretty hard to reproduce, happened 4 times out of 10-15 tries...
a) On a windows-amd64 platform, start SwingSet2 demo:
  $ cd M:/NightlyBuilds/re/6.0/promoted/rc/b96/binaries/windows-amd64
## which is /java/re/jdk/6.0/promoted/rc/b96/binaries/windows-amd64
  $ bin/java -jar demo/jfc/SwingSet2/SwingSet2.jar

b) As soon as the window appears (this is important), switch to Windows L&F
(click on "Look & Feel" menu, choose "Windows Look & Feel").
c) As fast as possible, click on the 3rd tab (JColorChooser Demo).
d) Exit the demo if it did not crash.. And repeat until it crashes.

Error message:
==============
# An unexpected error has been detected by Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0000000078edc97b, pid=2908, tid=1148
#
# Java VM: Java HotSpot(TM) 64-Bit Server VM (1.6.0-rc-b96 mixed mode)
# Problematic frame:
# C [ntdll.dll+0x1c97b]
#
# An error report file with more information is saved as C:\DOCUME~1\ADMINI~1.JCG\LOCALS~1\Temp\hs_err_pid2908.log
#

See Comments section for more info.
See the "hs_err_pidxxx.log" files attached.