Adjust Buttons to the widthest one

How can I do to make the buttons width adjust to the widthest one.

VerticalLayout midLeft = new VerticalLayout(btnAsignar, btnCombinar, btnReemplazar, btnCancelar);

If I setSizeFull() to some of them , they readjust to the biggest one, but if I set all them with SizeFull, the setting get lost

btn1.setSizeFull(); btn2.setSizeFull(); //btn3.setSizeFull(); //this is the one with a largest caption (for now) btn4.setSizeFull(); must be a better way to achieve this