$fields->addFieldsToTab('Root.Main', TextField::create('Title'));
$fields->addFieldsToTab('Root.Options', [ DropdownField::create('Color', 'Choose a color', ['Red', 'Green', 'Blue']), CheckboxField::create('Featured', 'Feature this product') ]);In this example, the addFieldsToTab function is again called on a FieldList object called "fields". The first argument specifies the "Options" tab, and the second argument is an array of two fields (a color dropdown and a featured checkbox). Package library: SilverStripe CMS