function TForm1.CurrText: TTextAttributes;
begin
  if edit.SelLength > 0 then Result := edit.SelAttributes
  else Result := edit.DefAttributes;
end;

function TForm1.GetColor(idx: Integer): TColor;
begin
    case idx of
      0 : result := clBlack;
      1 : result := clMaroon;
      2 : result := clGreen;
      3 : result := clOlive;
      4 : result := clNavy;
      5 : result := clPurple;
      6 : result := clGray;
      7 : result := clSilver;
      8 : result := clRed;
      9 : result := clLime;
      10 : result := clYellow;
      11 : result := clFuchsia;
      12 : result := clAqua;
      13 : result := clWhite;
      14 : result := clScrollBar;
      15 : result := clBackground;
    end;
end;

// ComboBox
procedure TForm1.ColorChange(Sender: TObject);
begin
CurrText.Color := CurrText.Color + getcolor(Color.ItemIndex);
end;