Freeze window does not work! Bug?!?

I am seeing some strange behaviour in FMP9 with the Freeze Window
script step. On a PC in XP pro

I have the following script steps in my Open Script that runs on file
open.

1 Go to Layout "Splash Screen"
2 Adjust window (maximize)
3 Freeze Window
4 Go to Layout "MemberDetail"

and then it goes on to perform a variety of other tasks, all within
this script. There are no external scripts called.

Anyway when the script hits the fourth step it switches to that layout
without the window staying frozen. I even put a pause at the end of
the script as the open script runs quickly - still does not stay on
the Splash Screen.

I check other scripts and they exhibit the same behaviour. Freeze
window does not work as documented in windows XP.

According to the documentation Freeze Window should do just that until
the script ends.

Any ideas? Am I misunderstanding something?

Darren