1. Create a reference to the control you wish to enable/disable. (You can right click on the control on the block diagram and select "Create >> Reference" to do this).
2. Wire the reference to a Property Node (found in Application Control on the Functions Palette).
3. Right click on the Property Node and choose "Change All To Write".
4. Left click on the Property Node and choose "Disabled" from the list.
The state of the control will depend on the value you wire to "Disabled" terminal of the Property Node. 0-Enabled, 1-Disabled, 2-Disabled and Grayed Out.
Hope that answers it for you.
Nick
"You keep using that word. I do not think it means what you think it means." - Inigo Montoya