Issue with List picker FullModeItemTemplate template

Issue with List picker FullModeItemTemplate template

I am using the Listpicker control in my WP8 app, where
FullModeItemTemplate is defined to display a custom list of options and I
enabled SelectionMode to Multiple, so that user can select multiple
options from the Listpicker. On code behind, i am binding the text.
My main question, with below my xaml output of the fullmode has lot of
free space between each list item. I couldn't able to figure out how to
minimize the gap between...
<toolkit:ListPicker x:Name="userCountryList" ItemsSource="{Binding
CountryList}" Header="Choose a country or region:"
SelectionMode="Multiple" FullModeItemTemplate="{StaticResource
DataTemplate2}" />
<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Key="DataTemplate2">
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" FontSize="28"
TextWrapping="Wrap" Text="{Binding CountryName}"
VerticalAlignment="Center" Width="Auto"/>
</StackPanel>
</DataTemplate>
</phone:PhoneApplicationPage.Resources>
Current fullmode output is like below: