diff --git a/code/model/Widget.php b/code/model/Widget.php
index 7eaad5c..a1444f4 100644
--- a/code/model/Widget.php
+++ b/code/model/Widget.php
@@ -159,10 +159,18 @@ class Widget extends DataObject {
 	 * @return FieldList
 	 */
 	public function getCMSFields() {
-		$fields = parent::getCMSFields();
+		$fields = $this->scaffoldFormFields(array(
+			// Don't allow has_many/many_many relationship editing before the record is first saved
+			'includeRelations' => ($this->ID > 0),
+			'tabbed' => false,
+			'ajaxSafe' => true
+		));
+		
 		$fields->removeByName('ParentID');
 		$fields->removeByName('Sort');
 		
+		$this->extend('updateCMSFields', $tabbedFields);
+		
 		return $fields;
 	}