if (colors == null || colors.length == 0) {
throw new IllegalArgumentException("Cannot be null nor empty:" +
"colors.");
}
this.colors = colors;
this.validator = new ColorValidator(colors);
createControls();
//Layout the control, that is, set the size and location
//of all of the ColorSelector's child widgets. This action
//allows me to get hold of the height of the Combo widget
//which I can then use to set the size of the ColorButton