title: toFade animation doing instantly, lenght property not working
body: <p>I want to fadeIn and fadeOut my frame when Tapped. When I tap, it instantly fadeout and fadein although I set 3000 milliseconds.</p>
  
  <p>I already tried Device.BeginInvokeOnMainThread but not working too.</p>
  
  <p>my xaml.cs:</p>
  
  <pre><code>private async void SelectedFrame_Tapped(object sender, EventArgs e)
      {            
          //Device.BeginInvokeOnMainThread( async() =&gt; { await questionFrame.FadeTo(0, 3000, Easing.SinInOut); });
          await questionFrame.FadeTo(0, 3000, Easing.SinInOut); 
      }
  </code></pre>
  
  <p>xaml:</p>
  
  <pre><code> &lt;Frame x:Name="questionFrame"
                         HorizontalOptions="FillAndExpand"
                         HasShadow="False"
                         VerticalOptions="Start"
                         BackgroundColor="WhiteSmoke"
                         CornerRadius="10"&gt;
                      &lt;StackLayout Margin="20"&gt;
                          &lt;Label Text="{Binding CurrentQuestionText}" FontSize="Micro"/&gt;
                          &lt;Label HeightRequest="10"/&gt;
                          &lt;Label Text="{Binding CurrentQuestion.Quest}"
                                 FontSize="Subtitle"/&gt;
                          &lt;Label HeightRequest="20"/&gt;
                          &lt;Frame CornerRadius="10" Padding="10"
                                 BorderColor="GhostWhite"
                                 BackgroundColor="White"&gt;
                              &lt;Label Text="{Binding CurrentQuestion.AnswerA}"
                                 FontSize="Small"&gt;
                                  &lt;Label.GestureRecognizers&gt;
                                      &lt;TapGestureRecognizer Command="{Binding GoToNextQuestionCommand}" Tapped="SelectedFrame_Tapped"/&gt;
                                  &lt;/Label.GestureRecognizers&gt;
                              &lt;/Label&gt;
                          &lt;/Frame&gt;
                      &lt;/StackLayout&gt;
                  &lt;/Frame&gt;
  </code></pre>