title: iOS - Select/Deselect the marker in Apple maps not working
body: <p>I am selecting multiple markers on maps. Marker selection is working perfectly and maps delegate method<br>
   <code>func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView){}</code> 
   is being called.</p>
  
  <ul>
  <li>When callout shown and i am going to deselect the same marker whose callout is showing. Nothing happened.</li>
  <li>When callout shown and i click on any other place and then deselect the previous marker it will deselect the marker.</li>
  </ul>
  
  <p><strong>Required:</strong></p>
  
  <p>When callout shown and i am going to deselect the same marker whose callout is showing that need to be deselect.</p>
  
  <p><strong>Used Stack</strong></p>
  
  <ul>
  <li><code>xCode</code> with <code>swift 4.2</code> </li>
  <li><code>Apple</code> MapKit</li>
  <li><code>MKAnnotationView</code> as Custom marker</li>
  </ul>
  
  <p>&nbsp;</p>
  
  <pre><code>class ArtworkView: MKAnnotationView {
  var locItem:LocationItem = LocationItem()
  
  
  override var annotation: MKAnnotation? {
    willSet {
      guard let artwork = newValue as? Artwork else {return}
      locItem = artwork.locItem
      if(!artwork.isUser){
          canShowCallout = true
          calloutOffset = CGPoint(x: -5, y: 5)
          rightCalloutAccessoryView = nil
          if let imageName = artwork.imageName {
              image = UIImage(named: imageName)
          } else {
              image = nil
          }
  
          detailCalloutAccessoryView = detailLabel
      }else{
          canShowCallout = false
          calloutOffset = CGPoint(x: -5, y: 5)
          rightCalloutAccessoryView = nil
          image = UIImage(named: "gifcurrentloc")
          detailCalloutAccessoryView = nil
      }
  
    }
  }
  </code></pre>