title: CollectionView SelectedItem is not highlighted in Xamarin Forms
body: <p>I am trying to highlight Xamarin Forms <code>CollectionView</code> Item, but it seems it doesn't highlight. While debugging I found out that if I remove the <code>SwipeView</code> <code>Gesture</code> event it works as expected. Additionally, in the current code the selection item is changed, but the color is not changning. How can I highlight the selected item?</p>
  
  <pre><code>&lt;CollectionView ItemsSource="{Binding SomeList}" 
  SelectedItem="{Binding CurrentItem}" SelectionMode="Single" x:Name="itemView"&gt;
  &lt;CollectionView.ItemsLayout&gt;
       &lt;GridItemsLayout Orientation="Vertical" Span="1"/&gt;
    &lt;/CollectionView.ItemsLayout&gt;
    &lt;CollectionView.ItemTemplate&gt;
      &lt;DataTemplate&gt;
      &lt;SwipeView&gt;
       &lt;SwipeView.GestureRecognizers&gt;
           &lt;SwipeGestureRecognizer Direction="Right"
            Command="{Binding BindingContext.SwipGestureCommand, Source={x:Reference itemView}}"
                                                              CommandParameter="right"/&gt;
     &lt;/SwipeView.GestureRecognizers&gt;
     &lt;StackLayout Orientation="Vertical" Padding="5"&gt;
      &lt;VisualStateManager.VisualStateGroups&gt;
           &lt;VisualStateGroup Name="CommonStates"&gt;
          &lt;VisualState Name="Normal" /&gt;
          &lt;VisualState Name="Selected"&gt;
               &lt;VisualState.Setters&gt;
                       &lt;Setter Property="BackgroundColor" Value="Yellow" /&gt;
               &lt;/VisualState.Setters&gt;
         &lt;/VisualState&gt;
        &lt;/VisualStateGroup&gt;
        &lt;/VisualStateManager.VisualStateGroups&gt;
            &lt;Label LineBreakMode="WordWrap"  Text="{Binding SomeText}"/&gt;
          &lt;/StackLayout&gt;
        &lt;/SwipeView&gt;
      &lt;/DataTemplate&gt;
    &lt;/CollectionView.ItemTemplate&gt;
  &lt;/CollectionView&gt;
  </code></pre>
  
  <p>How to highlight the selected collectionview item?</p>