Switching between "Windows and button" style on XP, color schemes on Vista is throwing an NPE.
Steps to reproduce:
 - Open SwingSet2, Switch to Windows LAF
 - Switch to ProgressBar demo.
 - Now open the Windows "Display Properties"
 - Navigate to the "Appearance" Tab
 - Change the "Windows & Buttons" from "Windows XP style" -> "Windows Classic style"
 - And Apply the same
 - You can see the NullPointerException now, the bug is reproduced

On Vista
 - You need change the "Color Scheme" from "Windows Vista Basic" to "Windows Classic"

This is reproducible on the latest build b98. Tried regressing it on XP till build b36, earlier build it's not consistent.

Stacktrace attached for both XP and Vista 5520.