The below example shows, in the same column, an icon related to the object type, and then a task.startDate. The icon has a fixed tooltip with text "Preview".

<ColStyle Name="Start" Width="150" Height="0" SortName="StartDate">

  <CellTemplate>

    <xp:StackPanel Orientation="Horizontal">

      <l:InfoPopup Margin="10,0,0,0" InfoId="{Binding Path=[task.id]}" VerticalAlignment="Top" DirectoryStyleName="Binding ObjectType.Name">

        <l:ObjectTypeIcon  ToolTip="Preview" MaxWidth="16" ObjectType="{Binding Path=ObjectType}"/>

      </l:InfoPopup>

      <xp:TextBlock Margin="4,0,4,0" Text="{Binding Path=[task.startDate], Converter={StaticResource StringFormatValueConverter}, ConverterParameter=\{0:g\}}" />

    </xp:StackPanel>

   </CellTemplate>

</ColStyle>