Cinema Display on/off switch wants to shut down/sleep MBP. Why?

[malch]

Hi there,
I have such a tangle of cables behind my MBP... just added a second fw hub, in fact. And now (don't know if it could be associated), when I try to turn my Cinema Display off (little switch at bottom right corner), instead of just turning off, up comes a message asking if I want to turn (my computer) off, or put it to sleep, etc.
Why this strange behaviour? Did a setting get changed? How can I fix it?
thanks,
malch

 

[killmoms]

A setting got changed. I believe this is in the Displays pane in System Preferences, under Options.

 

[malch]

A setting got changed. I believe this is in the Displays pane in System Preferences, under Options.

Thank you so much! Now I can sweep up the hair I tore out and get back to work.
malch