title: Xamarin Resource Dictionary with Dynamic Resource not updating
body: <p>I created 2 themes for my Xamarin app (Xamarin Forms v3.5). I merge the first one when app starts like so (in App.xaml):</p>
  
  <pre><code>&lt;ResourceDictionary&gt;
    &lt;ResourceDictionary Source="Styles/DarkResourceDictionary.xaml"/&gt;
  &lt;/ResourceDictionary&gt;
  </code></pre>
  
  <p>I change the theme in App.xaml.cs like so:</p>
  
  <pre><code>Current.Resources.MergedDictionaries.Clear();
          var resourceDictionary = new ResourceDictionary();
          resourceDictionary.SetAndLoadSource(uri, uri.ToString(), this.GetType().GetTypeInfo().Assembly, null);
          resourceDictionary.Source = uri;
          Current.Resources.MergedDictionaries.Add(resourceDictionary);
  </code></pre>
  
  <p>This works 100%, but the styles in the resource dictionaries are not applied until I re-open a form even though I use Dynamic Resource like so:</p>
  
  <pre><code>&lt;Grid Style="{DynamicResource DisplayBackground}"&gt;
  </code></pre>
  
  <p>Im sure Im overlooking something small. Any ideas? Thanks a bunch</p>