title: Python: ttk: disable/enable a button
body: <p>I want to change ttk.Button's state according to some internal logic. I create a button and associate a style with it:</p>
  
  <pre><code>cardBtnStyle = ttk.Style()
  cardBtnStyle.configure('CB.TButton')
  cardBtn = ttk.Button(top, text="Make SD card", style='CB.TButton', command = cardCreateCallBack).grid(column=1, row=5)
  </code></pre>
  
  <p>Following statement has no effect:</p>
  
  <pre><code>style.configure('CB.TButton', state='disabled')
  </code></pre>
  
  <p>But when I create a button like this, it is disabled:</p>
  
  <pre><code>cardBtn = ttk.Button(top, text="Make SD card", style='CB.TButton', state='disabled', command = cardCreateCallBack).grid(column=1, row=5)
  </code></pre>
  
  <p>How do I change ttk.Button state in Python?</p>
  
  <p>OS: Ubuntu 13.10</p>
  
  <p>Python: 2.7.5+</p>