UNIT Unit1;

{$mode objfpc}{$H+}

INTERFACE

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)
    LabelForCalculation: TLabel;
    Memo1: TMemo;
    Memo2: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure Memo1Change(Sender: TObject);
  private

  public

  end;

var
  Form1: TForm1;

IMPLEMENTATION

{$R *.lfm}

type
   TLabelCracker = class(TLabel);

//-----------------------------------------------------------
procedure TForm1.FormCreate(Sender: TObject);
begin
   LabelForCalculation.Visible := false;
   LabelForCalculation.AutoSize := true;
   LabelForCalculation.Font.Assign(Memo1.Font);

   Memo2.Font.Assign(Memo1.Font);
end;
//-----------------------------------------------------------
procedure TForm1.Memo1Change(Sender: TObject);
var
   sText : string;
begin
   sText := TrimRight(Memo1.Text);

   Memo2.Text := sText;
   LabelForCalculation.Caption := sText;

   //без этого принудительного вызова невидимый Label не пересчитает свой размер
   TLabelCracker(LabelForCalculation).DoAutoSize(); 

   Memo2.Width := LabelForCalculation.Width + 10;
   Memo2.Height := LabelForCalculation.Height + 10;
end;
//-----------------------------------------------------------

END.