title: Windows 8.1: Behaviors on Flyouts don't Work
body: <p>I am developing a windows 8.1 app using VS 2013 and MVVM Light.</p>
  
  <p>The following code shows the behavior in a flyout within an appbar:</p>
  
  <pre><code>&lt;AppBarButton.Flyout&gt;
      &lt;Flyout x:Name="FlyoutCalculator"
              Placement="Top"
              FlyoutPresenterStyle="{StaticResource FlyoutPresenterBaseStyle}"&gt;
  
          &lt;uc:Calculator ApplyCommand="{Binding CancelCommand}"
                         CancelCommand="{Binding CancelCommand}"                                           
                         Available="{Binding AvailableCounter, Mode=OneWay}"
                         SelectedItem="{Binding SelectedItem, Mode=TwoWay}"/&gt;
          &lt;interactivity:Interaction.Behaviors&gt;
              &lt;core:EventTriggerBehavior EventName="Opening"&gt;
                  &lt;core:InvokeCommandAction Command="{Binding ShowCurrentCostsCommand}" /&gt;
              &lt;/core:EventTriggerBehavior&gt;
          &lt;/interactivity:Interaction.Behaviors&gt;
      &lt;/Flyout&gt;
  &lt;/AppBarButton.Flyout&gt;
  </code></pre>
  
  <p>Unfortunately I get an exception while compiling the app:</p>
  
  <blockquote>
    <p>WinRT-Informationen: Cannot add instance of type <code>Microsoft.Xaml.Interactions.Core.EventTriggerBehavior</code> to a collection of type <code>Microsoft.Xaml.Interactivity.BehaviorCollection</code></p>
  </blockquote>
  
  <p>Other Behaviors in the View do work, does someone know a solution to this?</p>