I just modified Nancy's code from your message below and it appears to work. Can't figure out why it doesn't in our case yet...
Here is the test code that works:

CLOSE ALL
RELEASE ALL
CLEAR ALL

DELETE FILE ROTextbox.SC? RECYCLE

* Make a form
CREATE FORM ROTextbox NOWAIT
LOCAL laObject[1], lo
ASELOBJ(laObject,1)
lo = laObject[1]

* Add a grid with 1 column
lo.ADDOBJECT('grid1','grid')
lo.Grid1.COLUMNCOUNT = 1

* Make a simple cursor so the grid has something
* to bind to. Note, though, that this isn't
* necessary to trigger the issue.
lo.WRITEMETHOD("Load",;
  "CREATE CURSOR temp (l1 l)" + CHR(13) + ;
  "APPEND BLANK")

* Add code to the Grid's Init() to add a
* textbox at runtime and confirm it's invisible.
lo.Grid1.COLUMNS(1).WRITEMETHOD("Init",;
  "THIS.ADDOBJECT('text2','textbox')" + ;
  CHR(13) + ;
  "THIS.CURRENTCONTROL = 'text2'" + ;
  CHR(13) + ;
  "Messagebox('text2.Visible='+" + ;
  "TRANSFORM(This.text2.Visible))")

* Save and run the form.
KEYBOARD '{CTRL-W}'
DOEVENTS FORCE
DO FORM ROTextbox

CLOSE ALL
RELEASE ALL
CLEAR ALL

DELETE FILE ROTextbox.SC? RECYCLE

* Make a form
CREATE FORM ROTextbox NOWAIT
LOCAL laObject[1], lo
ASELOBJ(laObject,1)
lo = laObject[1]

* Add a grid with 1 column
lo.ADDOBJECT('grid1','grid')
lo.Grid1.COLUMNCOUNT = 1

* Make a simple cursor so the grid has something
* to bind to. Note, though, that this isn't
* necessary to trigger the issue.
lo.WRITEMETHOD("Load",;
  "CREATE CURSOR temp (l1 l)" + CHR(13) + ;
  "APPEND BLANK")

* Add code to the Grid's Init() to add a
* textbox at runtime and confirm it's invisible.
lo.Grid1.COLUMNS(1).WRITEMETHOD("Init",;
  "THIS.ADDOBJECT('text2','textbox')" + ;
  CHR(13) + ;
  "THIS.text2.visible = .T." +;
  CHR(13) + ;
  "THIS.CURRENTCONTROL = 'text2'" + ;
  CHR(13) + ;
  "Messagebox('text2.Visible='+" + ;
  "TRANSFORM(This.text2.Visible))")

* Save and run the form.
KEYBOARD '{CTRL-W}'
DOEVENTS FORCE
DO FORM ROTextbox

>Hi Tracy,
>
>I don't know why it doesn't works. See THREAD#848757 I had this exact problem and the visible property did the trick.