Or you can just use NAME clause

DEFINE WINDOW tt FROM 2,2 TO 45,24 NAME oDW
oDW.Left = oDW.Left + 200
oDW.Show()
...

>Define Window actually does create a form, with some special set of properties, so it looks that way. Try this:
>
>

DEFINE WINDOW tt FROM 2,2 TO 45,24
>ACTIVATE WINDOW tt
>o=_screen.Forms(1)
>o.Left = o.Left + 200
>