Mystery of TObjectList

procedure TformMain.btnTestClick(Sender: TObject);
var
  btn: TButton;
  btnCollection: TObjectList<TButton>;
  i: integer;
begin
  btnCollection := TObjectList<TButton>.Create(True);

  for i := 0 to 10 do
  begin
    btn := TButton.Create(Nil);
    btn.Parent := Self;
    btn.Left := i * 10;
    btn.Width := 100;
    btn.Top := 100;
    btn.Caption := VarToStr(i);
    btnCollection.Add(btn);
  end;

  btnCollection.Free;

  btnCollection := TObjectList<TButton>.Create(False);

  for i := 0 to 10 do
  begin
    btn := TButton.Create(Nil);
    btn.Parent := Self;
    btn.Left := i * 10;
    btn.Width := 100;
    btn.Top := 100;
    btn.Caption := VarToStr(i);
    btnCollection.Add(btn);
  end;

  for i := 0 to 10 do
  begin
    btnCollection.Items[i].Free;
  end;

  btnCollection.Free;
end;