title: How to conditionally disable a windows push button?
body: <p>I'm developing a simple application to allow the user to solve the towers of Hanoi puzzle. 
  I need to be able to conditionally disable some buttons on the interface.
  (i.e if a particular move is against the rules, the button for that move must be disable). </p>
  
  <p>How can I do this? </p>