public function getFieldConfiguration()
 {
     $fields = parent::getFieldConfiguration();
     // eventually replace hard-coded "Fields"?
     $baseName = "Fields[{$this->ID}]";
     $mask = $this->getSetting('TextMask');
     $extraFields = new FieldList(new TextField($baseName . "[CustomSettings][TextMask]", _t('EditableMaskedTextFieldWithDefault.MASK', 'Mask'), $mask), new LiteralField('MaskInstructions', _t('EditableMaskedTextFieldWithDefault.MASK_INSTRUCTIONS', 'Example: 99/99/9999 <ul><li>a - Represents an alpha character (A-Z,a-z)</li><li>9 - Represents a numeric character (0-9)</li><li>* - Represents an alphanumeric character (A-Z,a-z,0-9)</li></ul>')));
     $fields->merge($extraFields);
     return $fields;
 }
 function getFormField($properties = array())
 {
     $field = parent::getFormField('MaskedTextField');
     $field->setInputMask($this->getSetting('TextMask'));
     return $field;
 }