diff --git a/src/core/actor.js b/src/core/actor.js
index e4acb87..36f326d 100644
--- a/src/core/actor.js
+++ b/src/core/actor.js
@@ -58,10 +58,10 @@ Actor.prototype.setParent = function(parent, keep_local)
 		parent.obj.add(this.obj);
 	} else {
 		if (this.parent) {
-			THREE.SceneUtils.detach(this.obj, this.parent.obj, scene.obj);
+			scene.obj.attach(this.obj);
 		}
 		if (parent && parent !== scene) {
-			THREE.SceneUtils.attach(this.obj, scene.obj, parent.obj);
+			parent.obj.attach(this.obj);
 		}
 	}
 	if (this.parent) {
diff --git a/src/index.html b/src/index.html
index 9901b95..3f8808c 100644
--- a/src/index.html
+++ b/src/index.html
@@ -30,7 +30,6 @@
 
 		<script src="../lib/jscolor-2.0.5/jscolor.js"></script>
 
-		<script src="../node_modules/three/examples/js/utils/SceneUtils.js"></script>
 		<script src="../node_modules/three/examples/js/controls/TransformControls.js"></script>
 		<script src="../node_modules/three/examples/js/loaders/FBXLoader.js"></script>
 		<script src="../node_modules/three/examples/js/loaders/OBJLoader.js"></script>
diff --git a/src/views/scene-hierarchy.js b/src/views/scene-hierarchy.js
index 5d6efad..e0e93ab 100644
--- a/src/views/scene-hierarchy.js
+++ b/src/views/scene-hierarchy.js
@@ -38,8 +38,9 @@ function SceneHierarchyView(container, state)
 			check_callback: true,
 			data: self.buildHierarchy(scene),
 		},
-		plugins: ['state', 'dnd'],
+		plugins: ['state', 'dnd', 'types'],
 		state: {key: 'scene-hierarchy_state'},
+		types: {'#': {max_children: 1}},
 	});
 	this.tree = this.hierarchy.jstree(true);
 
@@ -166,7 +167,7 @@ SceneHierarchyView.prototype.onNodeMove = function(event, data)
 	if (data.parent != data.old_parent) {
 		let node = data.node;
 		let actor = scene.getActor(node.id);
-		let parent = scene.getActor(data.parent);
+		let parent = scene.getActor(data.parent) || scene;
 		actor.setParent(parent);
 		for (let sibling of this.tree.get_siblings(node)) {
 			if (sibling.data.order > node.data.order) {