Yes, you can add tooltip text to DataGridTextColumn - just stylize it
<DataGridTextColumn Header="ScreenName" Binding="{Binding ScreenName}" >
<DataGridTextColumn.CellStyle>
<Style TargetType="DataGridCell">
<Setter Property="ToolTip" Value="{Binding Name}" />
</Style>
</DataGridTextColumn.CellStyle>
</DataGridTextColumn>
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