function validateColor($sValue, \Formal\Form\Morphology $oMorpho, \Formal\Element $oElement)
{
if (!empty($sValue) && !preg_match("/^#[a-fA-F0-9]{6}([a-fA-F0-9]{2})?\$/", $sValue)) {
return "<strong>" . $oElement->option("label") . "</strong> is not a valid color with format '#RRGGBB' or '#RRGGBBAA' in hexadecimal values.";
}
return true;
}