"show window contents while dragging" choice not retained

Hello,

I am trying to permanently enable the "show window contents
while dragging" display effect in Windows XP Professional.
When I enable it, it remains in affect until the machine
is shut down or until I switch users. Either of those
events causes the option to be disabled.

There are two ways to set this via the Windowos UI -- I
have tried both and neither persists.

I can see that the registry contains several
DragFullWindows keys -- I am wondering if an inconsistent
registry might cause this or is this a Windows XP
Professional bug?

Thanks for any insight.

Bob