Spring RTS Engine

I am trying to use the relatively new gadget callin AllowWeaponTarget. I copied it from springcontent into the ZK gadget handler which I think I did successfully because I tested with Echo and it partially worked. I wrote a simple gadget to return false to all AllowWeaponTarget calls, this caused some units to not auto target (which is what I expected) but other units appeared unaffected. Has anyone else attempted to use this callin?

Suspect you need Script.SetWatchWeapon on for the weapondef or something?

That had no effect.