<ListBox ItemsSource="{Binding Path=UserMessages}" Grid.Row="2" Visibility="{Binding ElementName=ShowDetails, Path=IsChecked, Converter={StaticResource BoolToVisible}}" >
<ListBox.ItemTemplate>
<DataTemplate>
- <Expander Header="{Binding Message,FallbackValue='Seems we have a problem'}" FontWeight="Bold">
+ <Expander Header="{Binding Message,FallbackValue='Seems we have a problem'}" FontWeight="Bold" IsExpanded="true">
<TextBlock Text="{Binding Details,FallbackValue='This is a message'}" FontWeight="Normal" TextWrapping="Wrap" />
</Expander>
</DataTemplate>