The below example shows one or two blue rectangles, related to the copied to or copied from status of the displayed item, and also details, if you hower above the rectangle.

<ColStyle Name="D" Width="40">

  <CellTemplate>

    <StackPanel Orientation="Horizontal">

      <l:CopyActionsIndicator Value="{Binding Path=[linkObject:Dests]}" Foreground="#FF8cb2d6" Content="&#x25A0;" Header="Copied to:" />

      <l:CopyActionsIndicator Value="{Binding Path=[linkObject:Sources]}" Foreground="#FF8cb2d6" Content="&#x25A0;" Header="Copied from:" />

     </StackPanel>

   </CellTemplate>

</ColStyle>

Change indicator color

You may want to change the indicator color. Modify the color string in Foreground="...". For syntax, see Colors in XAML.