It depends on how you are defining "three-state" (which is quite different from 3-pole). Boolean variables will always have one of two states, True or False. A control cna be diasabled so that it cannot be changed by the user, but it will still have one of the two states.
If you need a three-state variable you could use a numeric control like a slider and customize the appearnce to have a True State, a False State, and a None State, where True = +1, False = -1, and None = 0.
Lynn
