title: Why MKCircle is not displayed on MKMapView iOS8
body: <p>I create new overlays like this:</p>
  
  <pre><code>MKCircle *circle = [MKCircle circleWithCenterCoordinate:region.coordinate radius:region.radius];
  [self.mapView addOverlay:circle];
  </code></pre>
  
  <p>also I implemented delegate method:</p>
  
  <pre><code>- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id&lt;MKOverlay&gt;)overlay {
      MKCircleRenderer *circleRenderer = [[MKCircleRenderer alloc] init];
      circleRenderer.fillColor = [UIColor greenColor];
      circleRenderer.alpha = 1.f;
      return circleRenderer;
  }
  </code></pre>
  
  <p>both parts of code are called, mapView != nil at that moment, it's delegate set,
  but I cannot see the circle on my map.</p>
  
  <p>What am I doing wrong?</p>