[Catublipas]

Código Delphi [-]
interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls, Vcl.Imaging.pngimage,
  Vcl.StdCtrls, Vcl.PlatformDefaultStyleActnCtrls, Vcl.Menus, Vcl.ActnPopup,
  Vcl.StdStyleActnCtrls, Vcl.ToolWin, Vcl.ActnMan, Vcl.ActnCtrls, Vcl.ActnMenus,
  System.Actions, Vcl.ActnList, Vcl.Grids, Vcl.DBGrids, Vcl.DBCGrids, Data.DB,
  IBX.IBCustomDataSet, IBX.IBQuery;

type
  TStringGrid = class(Vcl.Grids.TStringGrid);
  TEmpresasForm = class(TForm)
  ...
  procedure StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
  var CanSelect: Boolean);
  procedure StringGridContactosDrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
  procedure Paint; override;

  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  EmpresasForm: TEmpresasForm;
  iterador:Integer;
  R: TRect;

implementation

{$R *.dfm}

uses Login, FondoOscurecer, AnadirEmpresa, Contactos;
{ TStringgrid }
procedure TStringGrid.Paint;
begin
  inherited;
  R := CellRect(Col, Row);
  DrawFocusRect(Canvas.Handle, R);
end;
...