[ecfisa]

Hola Juampi.

Para ocultar el cursor del mouse en el Edit podes usar la función HideCaret.

Un ejemplo:

Código Delphi [-]
...

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    ...
    procedure FormCreate(Sender: TObject);
    ...
    procedure FormDestroy(Sender: TObject);
  private
    procedure ApplicationEventsIdle(Sender: TObject; var Done: Boolean);
  
  ...
  end;

...

procedure TForm1.FormCreate(Sender: TObject);
begin
  Application.OnIdle := ApplicationEventsIdle;
end;

...

procedure TForm1.FormDestroy(Sender: TObject);
begin
  Application.OnIdle := nil;
end;

procedure TForm1.ApplicationEventsIdle(Sender: TObject; var Done: Boolean);
begin
  HideCaret(Edit1.Handle);
end;

Saludos