"Lock screen" not working on a Windows standalone

[Bruce A. Pokras]

I have a single stack project made with Rev 2.5 that has arrow 
buttons for moving from one card to another. A simple:

lock screen
set lockmessages to true
go next
unlock screen with visual effect scroll right to card

works very well in a Mac standalone. However, when I click the arrow 
button in the corresponding  Windows standalone, the next card 
immediately appears and only _after_ that does the visual effect 
appear. So a user on Windows will see the next card _prior_ to the 
seeing the illusion of the next card sliding into view. Not very 
slick! Apparently, the "lock screen" command has not really locked 
the screen before the "go next" command was carried out.

I tried a different visual effect, but that did not help the problem. 
Has anyone else seen this problem? Any solutions or workarounds?

Regards,

Bruce Pokras
Blazing Dawn Software
www.blazingdawn.com