Program Lock on outlets not working?

[brockp]

Am I misunderstanding what Program Lock under options are?

 

First time using it, I added my first insteion on/off outlets.  2663-222 v.44   Brand new from Smarthomes last sale.

These have big buttons for manual control and whit little hands around I didn't want them putting devices into link mode.

In my isy994i/zw  running 4.7.3

If I set program lock under options I'm still able to put the outlet into link mode by pressing and holding buttons and getting a beep.  I also verified by putting the ISY into linking mode, and doing the press and hold set on the outlet and the ISY responds but notes that it's already linked.

 

Thoughts?   Am I misunderstanding what Program Lock means?  Is there another way to get my desired outcome?

 

Thanks