<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>