<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">

  <Grid.Resources>

    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"

                                    Source="{Binding Source={x:Static Application.Current}, 

                                                     Path=Orders}"/>

    <Style TargetType="{x:Type xcdg:DataCell}">

      <Setter Property="ToolTip"

              Value="{Binding RelativeSource={RelativeSource Self}, Path=Content}"/>

    </Style>

  </Grid.Resources>

  <xcdg:DataGridControl x:Name="OrdersGrid"

                       ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>        

</Grid>