How to strike text in stringgrid (delphi)

I would like to strike text of all cells from a line in a stringgrid by right click on that line. My code is about ok, but the clicked cell from the line is not striked (the other well)!?! Also, I have to click first on a line and then right click to proceed, I would like just to right click but don't know how :-/ My code:

procedure TForm1.StringGrid1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
  var
  i, j: integer;
begin
  if Button = mbRight then
  begin
    j:=StringGrid1.Selection.Top;
    If MessageDlg('Disable row '+IntToStr(j),
      mtConfirmation, [mbYes, mbNo], 0, mbYes) =mrYes then
    begin
      With Stringgrid1 As TStringGrid Do
        With Canvas Do
        begin
          for i := 0 to 2 do
          begin
            Rect := CellRect  (i, StringGrid1.Selection.Top);
            Font.Style := Font.Style + [fsStrikeOut];
            FillRect(Rect);
            DrawText(Canvas.Handle, PChar(Cells[i,j]), -1, Rect ,DT_CENTER );
          end;
        end;
    end;
  end;
end;

Wonderfull!!! But if I want to store the striked status I also add a column containing a 'x'; it works fine BUT when I create form I load the stringrid value and some 'x' in column 3, I try to use that code in form.create to strike these row but doesn't work :-(

for J := 1 to stringGrid1.RowCount-1   do
begin
if  stringGrid1.Cells[3,J]='x' then
for I:=1 to 2 do
    begin
    StringGrid1.Canvas.Font.Style := Font.Style + [fsStrikeOut];
    StringGrid1.Canvas.Brush.Color := clBtnFace; // title
    StringGrid1.Canvas.FillRect(Rect);
    Rect.Top := Rect.Top + 4;
    drawText(Canvas.Handle, PChar(StringGrid1.Cells[I, J]), -1, Rect, DT_CENTER);
    StringGrid1.Invalidate;
    end
  else
    begin
    StringGrid1.Canvas.Font.Style := Font.Style - [fsStrikeOut];
    StringGrid1.Canvas.Brush.Color := clBtnFace; // title
    StringGrid1.Canvas.FillRect(Rect);
    Rect.Top := Rect.Top + 4;
    drawText(Canvas.Handle, PChar(StringGrid1.Cells[I, J]), -1, Rect, DT_CENTER);
    StringGrid1.Invalidate;
    end;
end;

Any idea???