Lock screen… doesn't

Watch this video:

As you can see, the script of the button “Button” is very simple: it locks the screen, and repeats 25 times a go to the next card.

However, the lock screen command fails. Instead of seeing the first card until the script ends, when the last card should be shown, all of the cards are displayed in sequence.

I saw this error first in LiveCode 8.1.3.

You can see a larger version of the video here.

© David Neale 2017