diff --git a/src/Entity/Base/AbstractStructuralDBElement.php b/src/Entity/Base/AbstractStructuralDBElement.php
index b784ab2a..4384173f 100644
--- a/src/Entity/Base/AbstractStructuralDBElement.php
+++ b/src/Entity/Base/AbstractStructuralDBElement.php
@@ -322,6 +322,11 @@ abstract class AbstractStructuralDBElement extends AttachmentContainingDBElement
 
         $this->parent = $new_parent;
 
+        //Add this element as child to the new parent
+        if (null !== $new_parent) {
+            $new_parent->getChildren()->add($this);
+        }
+
         return $this;
     }
 
@@ -340,18 +345,28 @@ abstract class AbstractStructuralDBElement extends AttachmentContainingDBElement
     }
 
     /**
-     * @param static[]|Collection $elements
-     *
+     * Adds the given element as child to this element.
+     * @param  static  $child
      * @return $this
      */
-    public function setChildren($elements): self
+    public function addChild(self $child): self
     {
-        if (!is_array($elements) && !$elements instanceof Collection) {
-            throw new InvalidArgumentException('$elements must be an array or Collection!');
-        }
-
-        $this->children = $elements;
+        $this->children->add($child);
+        //Children get this element as parent
+        $child->setParent($this);
+        return $this;
+    }
 
+    /**
+     * Removes the given element as child from this element.
+     * @param  static  $child
+     * @return $this
+     */
+    public function removeChild(self $child): self
+    {
+        $this->children->removeElement($child);
+        //Children has no parent anymore
+        $child->setParent(null);
         return $this;
     }
 
diff --git a/src/Form/Type/Helper/StructuralEntityChoiceLoader.php b/src/Form/Type/Helper/StructuralEntityChoiceLoader.php
index 409b8837..6bca91b4 100644
--- a/src/Form/Type/Helper/StructuralEntityChoiceLoader.php
+++ b/src/Form/Type/Helper/StructuralEntityChoiceLoader.php
@@ -54,26 +54,6 @@ class StructuralEntityChoiceLoader extends AbstractChoiceLoader
         return array_merge($tmp, $this->builder->typeToNodesList($this->options['class'], null));
     }
 
-    /*public function loadChoicesForValues(array $values, callable $value = null)
-    {
-        $tmp = parent::loadChoicesForValues($values, $value);
-
-        if ($this->options['allow_add'] && empty($tmp)) {
-            if (count($values) > 1) {
-                throw new \InvalidArgumentException('Cannot add multiple entities at once.');
-            }
-
-            //Dont create a new entity for the empty option
-            if ($values[0] === "" || $values[0] === null) {
-                return $tmp;
-            }
-
-            return [$this->createNewEntitiesFromValue($values[0])[0]];
-        }
-
-        return $tmp;
-    }*/
-
     public function createNewEntitiesFromValue(string $value): array
     {
         if (!$this->options['allow_add']) {