becomeFirstResponder seems to work only 1st time for shake gesture
<p>I'm making my app shake-gesture-compatible by doing this in my UIViewController:</p>

<pre><code>- (void)viewWillAppear:(BOOL)animated
{
    [self.view becomeFirstResponder];
    [super viewWillAppear:animated];
}
</code></pre>

<p>The problem is that when I flip to another view (I'm using the "Utility App" template which has a flipside view and a root view controller to manage them both) the shake gesture ceases to work when I come back.</p>

<p>I see that the <code>viewWillAppear</code> method is called, it just doesn't seem that the view regains first responder status the second time around.</p>
