diff --git a/src/timeline/component/ItemSet.js b/src/timeline/component/ItemSet.js
index 97dab172..e2fe0b85 100644
--- a/src/timeline/component/ItemSet.js
+++ b/src/timeline/component/ItemSet.js
@@ -76,6 +76,7 @@ function ItemSet(backgroundPanel, axisPanel, labelPanel, options) {
 
   this.touchParams = {}; // stores properties while dragging
   // create the HTML DOM
+
   this._create();
 }
 
@@ -115,6 +116,9 @@ ItemSet.prototype._create = function _create(){
   this.dom.axis = axis;
   this.axisPanel.frame.appendChild(axis);
 
+  // create ungrouped Group
+  this._updateUngrouped();
+
   // attach event listeners
   // TODO: use event listeners from the rootpanel to improve performance?
   this.hammer = Hammer(frame, {
@@ -735,7 +739,7 @@ ItemSet.prototype._onUpdate = function _onUpdate(ids) {
     if (!item) {
       // create item
       if (constructor) {
-        item = new constructor(me, itemData, me.options, itemOptions);
+        item = new constructor(itemData, me.options, itemOptions);
         item.id = id; // TODO: not so nice setting id afterwards
         me._addItem(item);
       }
diff --git a/src/timeline/component/item/Item.js b/src/timeline/component/item/Item.js
index 6f6cef77..64cb5577 100644
--- a/src/timeline/component/item/Item.js
+++ b/src/timeline/component/item/Item.js
@@ -1,15 +1,14 @@
 /**
  * @constructor Item
- * @param {ItemSet | Group} parent
  * @param {Object} data             Object containing (optional) parameters type,
  *                                  start, end, content, group, className.
  * @param {Object} [options]        Options to set initial property values
  * @param {Object} [defaultOptions] default options
  *                                  // TODO: describe available options
  */
-function Item (parent, data, options, defaultOptions) {
+function Item (data, options, defaultOptions) {
   this.id = null;
-  this.parent = parent;
+  this.parent = null;
   this.data = data;
   this.dom = null;
   this.options = options || {};
diff --git a/src/timeline/component/item/ItemBox.js b/src/timeline/component/item/ItemBox.js
index df8d6fed..dd43d4a8 100644
--- a/src/timeline/component/item/ItemBox.js
+++ b/src/timeline/component/item/ItemBox.js
@@ -1,14 +1,13 @@
 /**
  * @constructor ItemBox
  * @extends Item
- * @param {ItemSet} parent
  * @param {Object} data             Object containing parameters start
  *                                  content, className.
  * @param {Object} [options]        Options to set initial property values
  * @param {Object} [defaultOptions] default options
  *                                  // TODO: describe available options
  */
-function ItemBox (parent, data, options, defaultOptions) {
+function ItemBox (data, options, defaultOptions) {
   this.props = {
     dot: {
       width: 0,
@@ -27,10 +26,10 @@ function ItemBox (parent, data, options, defaultOptions) {
     }
   }
 
-  Item.call(this, parent, data, options, defaultOptions);
+  Item.call(this, data, options, defaultOptions);
 }
 
-ItemBox.prototype = new Item (null, null);
+ItemBox.prototype = new Item (null);
 
 /**
  * Check whether this item is visible inside given range
diff --git a/src/timeline/component/item/ItemPoint.js b/src/timeline/component/item/ItemPoint.js
index eb6cca3f..6ab3111f 100644
--- a/src/timeline/component/item/ItemPoint.js
+++ b/src/timeline/component/item/ItemPoint.js
@@ -1,14 +1,13 @@
 /**
  * @constructor ItemPoint
  * @extends Item
- * @param {ItemSet} parent
  * @param {Object} data             Object containing parameters start
  *                                  content, className.
  * @param {Object} [options]        Options to set initial property values
  * @param {Object} [defaultOptions] default options
  *                                  // TODO: describe available options
  */
-function ItemPoint (parent, data, options, defaultOptions) {
+function ItemPoint (data, options, defaultOptions) {
   this.props = {
     dot: {
       top: 0,
@@ -28,10 +27,10 @@ function ItemPoint (parent, data, options, defaultOptions) {
     }
   }
 
-  Item.call(this, parent, data, options, defaultOptions);
+  Item.call(this, data, options, defaultOptions);
 }
 
-ItemPoint.prototype = new Item (null, null);
+ItemPoint.prototype = new Item (null);
 
 /**
  * Check whether this item is visible inside given range
diff --git a/src/timeline/component/item/ItemRange.js b/src/timeline/component/item/ItemRange.js
index 706555cc..3a28212d 100644
--- a/src/timeline/component/item/ItemRange.js
+++ b/src/timeline/component/item/ItemRange.js
@@ -1,14 +1,13 @@
 /**
  * @constructor ItemRange
  * @extends Item
- * @param {ItemSet} parent
  * @param {Object} data             Object containing parameters start, end
  *                                  content, className.
  * @param {Object} [options]        Options to set initial property values
  * @param {Object} [defaultOptions] default options
  *                                  // TODO: describe available options
  */
-function ItemRange (parent, data, options, defaultOptions) {
+function ItemRange (data, options, defaultOptions) {
   this.props = {
     content: {
       width: 0
@@ -25,10 +24,10 @@ function ItemRange (parent, data, options, defaultOptions) {
     }
   }
 
-  Item.call(this, parent, data, options, defaultOptions);
+  Item.call(this, data, options, defaultOptions);
 }
 
-ItemRange.prototype = new Item (null, null);
+ItemRange.prototype = new Item (null);
 
 ItemRange.prototype.baseClassName = 'item range';
 
diff --git a/src/timeline/component/item/ItemRangeOverflow.js b/src/timeline/component/item/ItemRangeOverflow.js
index a94c7cab..156123f6 100644
--- a/src/timeline/component/item/ItemRangeOverflow.js
+++ b/src/timeline/component/item/ItemRangeOverflow.js
@@ -1,14 +1,13 @@
 /**
  * @constructor ItemRangeOverflow
  * @extends ItemRange
- * @param {ItemSet} parent
  * @param {Object} data             Object containing parameters start, end
  *                                  content, className.
  * @param {Object} [options]        Options to set initial property values
  * @param {Object} [defaultOptions] default options
  *                                  // TODO: describe available options
  */
-function ItemRangeOverflow (parent, data, options, defaultOptions) {
+function ItemRangeOverflow (data, options, defaultOptions) {
   this.props = {
     content: {
       left: 0,
@@ -16,10 +15,10 @@ function ItemRangeOverflow (parent, data, options, defaultOptions) {
     }
   };
 
-  ItemRange.call(this, parent, data, options, defaultOptions);
+  ItemRange.call(this, data, options, defaultOptions);
 }
 
-ItemRangeOverflow.prototype = new ItemRange (null, null);
+ItemRangeOverflow.prototype = new ItemRange (null);
 
 ItemRangeOverflow.prototype.baseClassName = 'item rangeoverflow';