title: Hide a ContentControl
body: <p>Below is a fine piece of artwork that represents a WPF form with a listbox on the left and a content control on the right.  I would like to set it so if the list box is empty, then the content control is invisible.  What property/event should I hook to?</p>
  
  <pre><code>----- -----
  | a | | c |
  | b | |   |
  ----- -----
  </code></pre>