What method did you put this code in? And did you override that method in the instance? BTW, the way I'd do this is in the textbox GotFocus:

if not empty(this.value)
   keyboard "{End}"
endif 

>Hi all.
>
>I want to position the text entry cursor at the end of a prefilled string in a textbox. This works fine with the textbox base class, but not with ctextboxl. My code snippet is as follows, where oItemCode is the instance of ctextboxl:
>
>With Thisform
> If .lAddMode or Empty(.oItemCode.TextBox.Value)
> .oItemCode.TextBox.Value = v_vendor.VendNr
> .oItemCode.TextBox.SelStart = len(.oItemCode.TextBox.Value)
> Endif .lAddMode or ...
>Endwith
>
>Clues, anyone?
>
>Dan