Reading the First Line of a DataGrid

[Mark Stuart]

Hi all,
I'm trying to get the first line of a loaded DataGrid to be selected.

At the end of the script that loads the DataGrid, I have the following 2
lines:
	set the dgLine of grp "DataGrid" to 1
	send "selectionChanged" to grp "DataGrid"

I've also tried:
      set the dgLine of grp "DataGrid" to 1
	dispatch "selectionChanged" to grp "DataGrid"

This really isn't selecting the line at all.
How do I know, because in the selectionChanged handler of the DataGrid I'm
using the answer command to display the arguments of the handler:
HilitedIndex and PrevHilitedIndex.
These values are empty using: 
	answer "HilitedIndex:" && HilitedIndex & cr & "PrevHilitedIndex:" &&
PrevHilitedIndex

So how do I get the first line of a DataGrid to be selected?

Regards,
Mark Stuart