title: Can't get EVT_KEY_DOWN to fire in wxPerl
body: <p>In this case <code>$self</code> is a subclass of <code>Wx::Frame</code> and I can add controls, menus, etc to the frame.  However I cannot add key events.  I am using the following to add the key event:</p>
  
  <pre><code>  EVT_KEY_DOWN($self,  \&amp;_process_char);
  </code></pre>
  
  <p>The _process_char function looks like this:</p>
  
  <pre><code>sub _process_char {
     my ($evt) = @_;
     warn 'key pressed';
  }
  </code></pre>
  
  <p>The event doesn't fire.  What am I doing wrong?  How do I get key down events to work with wxperl?</p>