proximityMonitoringEnabled for modally presented view controller
<p>In a <code>UIViewController</code> I'm using this code snippet which works absolutely fine:</p>

<pre><code>- (void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];

    [UIDevice currentDevice].proximityMonitoringEnabled = YES; 
}
</code></pre>

<p>Then I'm detecting interface rotation changes to present another <code>UIViewController</code> modally via performing a segue:</p>

<pre><code>- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {

    if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {

        [self performSegueWithIdentifier:@"showAnotherView" sender:nil];
    }
}
</code></pre>

<p>In this modally presented view controller I'm now doing the same, I enable proximity monitoring in <code>viewWillAppear:</code></p>

<p>Unfortunately this doesn't work: The display doesn't turn off when I'm covering the proximity sensor of my iPhone 5.</p>

<p>What am I doing wrong?</p>
