I'm working with MEF and Caliburn.Mirco. My XAML-Code looks like this.

<igOutlookBar:XamOutlookBar DockPanel.Dock="Left" GroupsSource="{Binding Modules}" Width="200" AllowMinimized="True">
  <igOutlookBar:XamOutlookBar.Resources>
    <Style TargetType="{x:Type igOutlookBar:OutlookBarGroup}" >
      <Setter Property="Header" Value="{Binding Path=DisplayName}"/>
      <Setter Property="Content" Value="{Binding}"/>
      <Setter Property="ContentTemplate">
        <Setter.Value>
          <DataTemplate>
            <ContentControl cal:View.Model="{Binding}" />
          </DataTemplate>
        </Setter.Value>
      </Setter>
    </Style>
  </igOutlookBar:XamOutlookBar.Resources>
</igOutlookBar:XamOutlookBar>

This works nice as long as I don't minimize the XamOutlookBar. 

But when its minimized and the popup appears the second time my view is no longer displayed.

Then everything goes wrong. Sometimes the view appears, sometimes not. Even if the bar is minimized or not.

I think, because it usually works, the problem has something to do with the minimization.

Any advices?