diff --git a/api/migrations/schema/Version20250324224924.php b/api/migrations/schema/Version20250324224924.php
new file mode 100644
index 0000000000..789a1c61a8
--- /dev/null
+++ b/api/migrations/schema/Version20250324224924.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20250324224924 extends AbstractMigration {
+    public function getDescription(): string {
+        return 'ContentNode.RootId not nullable';
+    }
+
+    public function up(Schema $schema): void {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE content_node ALTER rootId SET NOT NULL');
+    }
+
+    public function down(Schema $schema): void {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE content_node ALTER rootid DROP NOT NULL');
+    }
+}
diff --git a/api/src/Entity/ContentNode.php b/api/src/Entity/ContentNode.php
index 736104c7d0..ebf2442f4c 100644
--- a/api/src/Entity/ContentNode.php
+++ b/api/src/Entity/ContentNode.php
@@ -62,7 +62,7 @@ abstract class ContentNode extends BaseEntity implements BelongsToContentNodeTre
     #[Gedmo\SortableGroup] // this is needed to avoid that all root nodes are in the same sort group (parent:null, slot: '')
     #[Groups(['read'])]
     #[ORM\ManyToOne(targetEntity: ColumnLayout::class, inversedBy: 'rootDescendants')]
-    #[ORM\JoinColumn(nullable: true, onDelete: 'CASCADE')] // TODO make not null in the DB using a migration, and get fixtures to run
+    #[ORM\JoinColumn(nullable: false, onDelete: 'CASCADE')]
     public ?ColumnLayout $root = null;
 
     /**
@@ -186,6 +186,11 @@ public function getParent(): ?HasParentInterface {
         return $this->parent;
     }
 
+    public function setParent(?ContentNode $parent) {
+        $this->parent = $parent;
+        $this->root ??= $parent?->root;
+    }
+
     /**
      * Holds the actual data of the content node.
      */
diff --git a/api/tests/Api/ContentNodes/RootColumnLayout/CreateRootColumnLayoutTest.php b/api/tests/Api/ContentNodes/RootColumnLayout/CreateRootColumnLayoutTest.php
index 8baf213391..dd74aa8e86 100644
--- a/api/tests/Api/ContentNodes/RootColumnLayout/CreateRootColumnLayoutTest.php
+++ b/api/tests/Api/ContentNodes/RootColumnLayout/CreateRootColumnLayoutTest.php
@@ -35,7 +35,7 @@ public function testCreateColumnLayoutValidatesMissingParent() {
         $this->assertJsonContains([
             'violations' => [
                 [
-                    'propertyPath' => 'parent',
+                    'propertyPath' => 'root',
                     'message' => 'This value should not be null.',
                 ],
             ],
diff --git a/api/tests/Api/SnapshotTests/__snapshots__/ResponseSnapshotTest__testOpenApiSpecMatchesSnapshot__1.yml b/api/tests/Api/SnapshotTests/__snapshots__/ResponseSnapshotTest__testOpenApiSpecMatchesSnapshot__1.yml
index 0e7a0a4de4..b47bb34338 100644
--- a/api/tests/Api/SnapshotTests/__snapshots__/ResponseSnapshotTest__testOpenApiSpecMatchesSnapshot__1.yml
+++ b/api/tests/Api/SnapshotTests/__snapshots__/ResponseSnapshotTest__testOpenApiSpecMatchesSnapshot__1.yml
@@ -8428,9 +8428,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -8445,6 +8443,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ChecklistNode-write_create:
       deprecated: false
@@ -8686,9 +8685,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -8703,6 +8700,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ChecklistNode.jsonhal-read:
       deprecated: false
@@ -8795,9 +8793,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -8812,6 +8808,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ChecklistNode.jsonhal-write_create:
       deprecated: false
@@ -9002,9 +8999,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9019,6 +9014,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ChecklistNode.jsonld-write_create:
       deprecated: false
@@ -9175,9 +9171,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9192,6 +9186,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout-read_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries:
       deprecated: false
@@ -9273,9 +9268,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9290,6 +9283,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -9371,9 +9365,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9388,6 +9380,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -9469,9 +9462,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9486,6 +9477,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout-read_ScheduleEntry.Activity:
       deprecated: false
@@ -9567,9 +9559,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9584,6 +9574,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout-write_create:
       deprecated: false
@@ -9792,9 +9783,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9809,6 +9798,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-read:
       deprecated: false
@@ -9899,9 +9889,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -9916,6 +9904,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-read_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries:
       deprecated: false
@@ -10006,9 +9995,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10023,6 +10010,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -10113,9 +10101,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10130,6 +10116,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -10220,9 +10207,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10237,6 +10222,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-read_ScheduleEntry.Activity:
       deprecated: false
@@ -10327,9 +10313,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10344,6 +10328,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonhal-write_create:
       deprecated: false
@@ -10525,9 +10510,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10542,6 +10525,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonld-read_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries:
       deprecated: false
@@ -10646,9 +10630,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10663,6 +10645,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonld-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -10767,9 +10750,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10784,6 +10765,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonld-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -10888,9 +10870,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -10905,6 +10885,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonld-read_ScheduleEntry.Activity:
       deprecated: false
@@ -11009,9 +10990,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11026,6 +11005,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ColumnLayout.jsonld-write_create:
       deprecated: false
@@ -11174,9 +11154,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11190,6 +11168,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -11265,9 +11244,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11281,6 +11258,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -11356,9 +11334,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11372,6 +11348,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonapi:
       deprecated: false
@@ -11453,9 +11430,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11469,6 +11444,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonhal-read:
       deprecated: false
@@ -11558,9 +11534,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11574,6 +11548,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonhal-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -11658,9 +11633,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11674,6 +11647,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonhal-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -11758,9 +11732,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11774,6 +11746,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonld-read:
       deprecated: false
@@ -11860,9 +11833,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11876,6 +11847,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonld-read_Activity.Category_Activity.ActivityProgressLabel_Activity.ActivityResponsibles_Activity.ScheduleEntries_Activity.ContentNodes:
       deprecated: false
@@ -11974,9 +11946,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -11990,6 +11960,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentNode.jsonld-read_Category.PreferredContentTypes_Category.ContentNodes:
       deprecated: false
@@ -12088,9 +12059,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -12104,6 +12073,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     ContentType-read:
       deprecated: false
@@ -14525,9 +14495,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -14542,6 +14510,7 @@ components:
         - contentType
         - materialItems
         - position
+        - root
       type: object
     MaterialNode-write_create:
       deprecated: false
@@ -14735,9 +14704,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -14752,6 +14719,7 @@ components:
         - contentType
         - materialItems
         - position
+        - root
       type: object
     MaterialNode.jsonhal-read:
       deprecated: false
@@ -14840,9 +14808,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -14857,6 +14823,7 @@ components:
         - contentType
         - materialItems
         - position
+        - root
       type: object
     MaterialNode.jsonhal-write_create:
       deprecated: false
@@ -15029,9 +14996,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -15046,6 +15011,7 @@ components:
         - contentType
         - materialItems
         - position
+        - root
       type: object
     MaterialNode.jsonld-write_create:
       deprecated: false
@@ -15188,9 +15154,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -15204,6 +15168,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     MultiSelect-write_create:
       deprecated: false
@@ -15411,9 +15376,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -15427,6 +15390,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     MultiSelect.jsonhal-read:
       deprecated: false
@@ -15517,9 +15481,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -15533,6 +15495,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     MultiSelect.jsonhal-write_create:
       deprecated: false
@@ -15713,9 +15676,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -15729,6 +15690,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     MultiSelect.jsonld-write_create:
       deprecated: false
@@ -18434,9 +18396,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -18451,6 +18411,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ResponsiveLayout-write_create:
       deprecated: false
@@ -18668,9 +18629,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -18685,6 +18644,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ResponsiveLayout.jsonhal-read:
       deprecated: false
@@ -18778,9 +18738,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -18795,6 +18753,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ResponsiveLayout.jsonhal-write_create:
       deprecated: false
@@ -18982,9 +18941,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -18999,6 +18956,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     ResponsiveLayout.jsonld-write_create:
       deprecated: false
@@ -20675,9 +20633,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -20692,6 +20648,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     SingleText-write_create:
       deprecated: false
@@ -20891,9 +20848,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -20908,6 +20863,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     SingleText.jsonhal-read:
       deprecated: false
@@ -20995,9 +20951,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21012,6 +20966,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     SingleText.jsonhal-write_create:
       deprecated: false
@@ -21187,9 +21142,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21204,6 +21157,7 @@ components:
         - contentType
         - data
         - position
+        - root
       type: object
     SingleText.jsonld-write_create:
       deprecated: false
@@ -21351,9 +21305,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21367,6 +21319,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     Storyboard-write_create:
       deprecated: false
@@ -21577,9 +21530,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21593,6 +21544,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     Storyboard.jsonhal-read:
       deprecated: false
@@ -21684,9 +21636,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21700,6 +21650,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     Storyboard.jsonhal-write_create:
       deprecated: false
@@ -21882,9 +21833,7 @@ components:
           example: /content_nodes/1a2b3c4d
           format: iri-reference
           readOnly: true
-          type:
-            - 'null'
-            - string
+          type: string
         slot:
           description: |-
             The name of the slot in the parent in which this content node resides. The valid slot names
@@ -21898,6 +21847,7 @@ components:
         - children
         - contentType
         - position
+        - root
       type: object
     Storyboard.jsonld-write_create:
       deprecated: false