[[ArdiIIa]]

Utiliza un TRichEdit y podrás controlar el cambio de color...

Código Delphi [-]
procedure TForm1.Button1Click(Sender: TObject);

begin
  with RichEdit1.SelAttributes do
  begin
    Color := clRed;
    Height := Height + 5;
  end;
  RichEdit1.Lines.Add('This line of text will be red.');
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  RichEdit1.DefAttributes.Color := clBlue;
  RichEdit1.DefAttributes.Style := [fsBold, fsItalic];
end;