Código Delphi [-]
 procedure TForm1.StringGrid1MouseDown(Sender: TObject; Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
  Var
   Valor :String;
   LGcCoord: TGridCoord; //Define las cordenadas del mouse en el grid
 begin
   LGcCoord := TCustomGrid(StringGrid1).MouseCoord(x,y);
   GiCol := LGcCoord.X; //Establece la columna seleccionada
   GiRow := LGcCoord.Y; //Establece la fila seleccionada
   if (GiRow = 0) And (Button = mbleft) And (GiCol <> -1) then
     Begin
       with stringgrid1 do
         Begin
           GCelda := CellRect(GiCol,0);
           Valor := Cells[GiCol, 0];
           Canvas.Font := Font;
           Canvas.Brush.Color := clBtnFace;
           Canvas.FillRect(GCelda);
           Canvas.TextRect(GCelda, GCelda.Left + 2, GCelda.Top + 2, Valor);
           DrawEdge(Canvas.Handle, GCelda, 10, 2 or 4 or 8);
           DrawEdge(Canvas.Handle, GCelda, 2 or 4, 1);
         End;
      End;
 End;
 procedure TForm1.StringGrid1MouseUp(Sender: TObject; Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
  Var
   Valor :String;
 begin
   if (GiRow = 0) And (Button = mbleft) And (GiCol <> -1) then
     Begin
       with stringgrid1 do
         Begin
           Valor := Cells[Gicol, 0];
           Canvas.Font := Font;
           Canvas.Brush.Color := clBtnFace;
           Canvas.FillRect(GCelda);
           Canvas.TextRect(GCelda, GCelda.Left + 2, GCelda.Top + 2, Valor);
           DrawEdge(Canvas.Handle, GCelda, 4, 4 or 8);
           DrawEdge(Canvas.Handle, GCelda, 4, 1 or 2);
           GCelda := stringgrid1.CellRect(1, 1);
         End;
     End;
 end;