class NivoSliderWidget extends Widget {

   static $db = array(
      'effect' => "Enum('sliceDown,sliceDownLeft,sliceUp,sliceUpLeft,sliceUpDown,sliceUpDownLeft,fold,fade,random','random')",
      ...
   );

   static $has_many = array('NivoSliderItems' => 'NivoSliderItem');
      
   public function getCMSFields() {
      $f = new FieldSet(
         new DropdownField('effect',"Effect", singleton('NivoSliderWidget')->dbObject('effect')->enumValues()),
         ...
         new TextField('captionOpacity','Universal caption opacity 0-1'),
         new TabSet("Tabs",
            new Tab("Items",
               new DataObjectManager($this, 'NivoSliderItems', 'NivoSliderItem', array(
                  'Thumbnail' => _t('Image.PLURALNAME'),
                  'Title' => _t('SiteTree.METATITLE'),
                  'Tagline' => _t('SiteTree.METADESC')),
                  'getCMSFields_forPopup'
               )
            )
         )
   );
      return $f;
   }

class NivoSliderItem extends DataObject {
   static $db = array (
      'Title' => 'Text',
      'Tagline' => 'Text'
   );

   static $has_one = array(
      'NivoSliderWidget' => 'NivoSliderWidget',
      'PanelImage' => 'Image',
   'PanelLink' => 'SiteTree'
   );
   
   static $api_access = true;
   
   public function getCMSFields_forPopup(){
    $image=class_exists('ImageUploadField')?'ImageUploadField':'FileIFrameField';
    $tree=class_exists('SimpleTreeDropdownField')?'SimpleTreeDropdownField':'HTMLDropdownField';
   
    $imager=new $image('PanelImage',_t('Image.SINGULARNAME')." ...");
   
    if($image=='ImageUploadField')$imager->uploadOnSubmit();   
   
      return new FieldSet(
         new TextField('Title',_t('SiteTree.METATITLE')),
         new TextField('Tagline',_t('SiteTree.METADESC')),
         $imager,
         new $tree("PanelLinkID",_t('RedirectorPage.REDIRECTTOPAGE'),"SiteTree")
      );
   }
....