public function modifyFormFields(FieldList $fields, SiteTreeNodeInterface $page)
{
$fields('main')->offsetUnset('content');
$linkTypes = array('internal' => Lang::get('cmsable::models.page.enums.redirect_type.internal'), 'external' => Lang::get('cmsable::models.page.enums.redirect_type.external'));
$selectGroup = SelectOneGroup::create('redirect_type', Lang::get('cmsable::models.page.fields.redirect_type'))->setSrc($linkTypes);
$selectGroup->push($this->getSiteTreeSelect($page));
$selectGroup->push(TextField::create('redirect__redirect_target_e', Lang::get('cmsable::forms.page-form.redirect_target_e')));
$fields('main')->push($selectGroup);
}
$surname = new TextField('surname', 'Please enter your surname');
$surname->setValue('Batten');
$rememberMe = new CheckboxField('remember', 'Remember Me');
$rememberMyRadio = new BooleanRadioField('rememberMyRadio');
$rememberMyRadio->trueString = 'Remember my Radio';
$rememberMyRadio->falseString = 'Forget my Radio';
$rememberMyRadio->setValue(TRUE);
$container = new FieldList('group1', 'Tab One');
$container->setSwitchable(TRUE);
$form->push($container);
$container->push($name)->push($surname)->push($rememberMe)->push($rememberMyRadio);
$container2 = new FieldList('group2', 'Tab Two');
$container2->setSwitchable(TRUE);
// $container2->push($category)->push($tagsField)->push($category2)->push($tags2);
$linkTypes = array('internal' => 'Internal', 'external' => 'External');
$selectGroup = SelectOneGroup::create('linkType', 'Link')->setSrc($linkTypes);
$selectGroup->setValue('internal');
$targets = array('firstchild' => 'First Child Page', '1' => 'Home', '2' => 'Contact', '3' => 'About us');
$pages = SelectOneField::create('internalTarget', 'Target')->setSrc($targets);
$selectGroup->push($pages);
$externalTarget = TextField::create('externalTarget', 'URL');
$selectGroup->push($externalTarget);
$container2->push($selectGroup);
$form->push($container2);
$form->actions->push(Action::create('delete')->setTitle('Delete'));
$form('surname')->setValue('Button');
$nameValidator = new TextValidator();
$nameValidator->required = FALSE;
$nameValidator->minLength = 3;
$nameValidator->setMaxLength = 12;
$requiredValidator = new RequiredValidator();
