diff --git a/HISTORY.md b/HISTORY.md
index 1a67644b..55884a46 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -12,6 +12,7 @@ http://visjs.org
 ### Network
 
 - Fixed #1343: Connected edges are now deselected too when deselecting a node.
+- Fixed #1398: Support nodes start with the correct positions.
 
 ### Timeline
 
diff --git a/dist/vis.js b/dist/vis.js
index 1cd3b413..0667889e 100644
--- a/dist/vis.js
+++ b/dist/vis.js
@@ -5,7 +5,7 @@
  * A dynamic, browser-based visualization library.
  *
  * @version 4.9.1-SNAPSHOT
- * @date    2015-10-06
+ * @date    2015-11-02
  *
  * @license
  * Copyright (C) 2011-2015 Almende B.V, http://almende.com
@@ -563,11 +563,11 @@ return /******/ (function(modules) { // webpackBootstrap
             // object is an ASP date
             return new Date(Number(match[1])); // parse number
           } else {
-            return moment(object).toDate(); // parse string
-          }
+              return moment(object).toDate(); // parse string
+            }
         } else {
-          throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type Date');
-        }
+            throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type Date');
+          }
 
       case 'Moment':
         if (exports.isNumber(object)) {
@@ -584,11 +584,11 @@ return /******/ (function(modules) { // webpackBootstrap
             // object is an ASP date
             return moment(Number(match[1])); // parse number
           } else {
-            return moment(object); // parse string
-          }
+              return moment(object); // parse string
+            }
         } else {
-          throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type Date');
-        }
+            throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type Date');
+          }
 
       case 'ISODate':
         if (exports.isNumber(object)) {
@@ -603,11 +603,11 @@ return /******/ (function(modules) { // webpackBootstrap
             // object is an ASP date
             return new Date(Number(match[1])).toISOString(); // parse number
           } else {
-            return new Date(object).toISOString(); // parse string
-          }
+              return new Date(object).toISOString(); // parse string
+            }
         } else {
-          throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type ISODate');
-        }
+            throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type ISODate');
+          }
 
       case 'ASPDate':
         if (exports.isNumber(object)) {
@@ -621,8 +621,8 @@ return /******/ (function(modules) { // webpackBootstrap
             // object is an ASP date
             value = new Date(Number(match[1])).valueOf(); // parse number
           } else {
-            value = new Date(object).valueOf(); // parse string
-          }
+              value = new Date(object).valueOf(); // parse string
+            }
           return '/Date(' + value + ')/';
         } else {
           throw new Error('Cannot convert object of type ' + exports.getType(object) + ' to type ASPDate');
@@ -854,13 +854,13 @@ return /******/ (function(modules) { // webpackBootstrap
     if (element.addEventListener) {
       if (useCapture === undefined) useCapture = false;
 
-      if (action === 'mousewheel' && navigator.userAgent.indexOf('Firefox') >= 0) {
-        action = 'DOMMouseScroll'; // For Firefox
+      if (action === "mousewheel" && navigator.userAgent.indexOf("Firefox") >= 0) {
+        action = "DOMMouseScroll"; // For Firefox
       }
 
       element.addEventListener(action, listener, useCapture);
     } else {
-      element.attachEvent('on' + action, listener); // IE browsers
+      element.attachEvent("on" + action, listener); // IE browsers
     }
   };
 
@@ -876,14 +876,14 @@ return /******/ (function(modules) { // webpackBootstrap
       // non-IE browsers
       if (useCapture === undefined) useCapture = false;
 
-      if (action === 'mousewheel' && navigator.userAgent.indexOf('Firefox') >= 0) {
-        action = 'DOMMouseScroll'; // For Firefox
+      if (action === "mousewheel" && navigator.userAgent.indexOf("Firefox") >= 0) {
+        action = "DOMMouseScroll"; // For Firefox
       }
 
       element.removeEventListener(action, listener, useCapture);
     } else {
       // IE browsers
-      element.detachEvent('on' + action, listener);
+      element.detachEvent("on" + action, listener);
     }
   };
 
@@ -896,8 +896,8 @@ return /******/ (function(modules) { // webpackBootstrap
     if (event.preventDefault) {
       event.preventDefault(); // non-IE browsers
     } else {
-      event.returnValue = false; // IE browsers
-    }
+        event.returnValue = false; // IE browsers
+      }
   };
 
   /**
@@ -1062,17 +1062,17 @@ return /******/ (function(modules) { // webpackBootstrap
    * @returns {*}
    */
   exports.overrideOpacity = function (color, opacity) {
-    if (color.indexOf('rgba') != -1) {
+    if (color.indexOf("rgba") != -1) {
       return color;
-    } else if (color.indexOf('rgb') != -1) {
-      var rgb = color.substr(color.indexOf('(') + 1).replace(')', '').split(',');
-      return 'rgba(' + rgb[0] + ',' + rgb[1] + ',' + rgb[2] + ',' + opacity + ')';
+    } else if (color.indexOf("rgb") != -1) {
+      var rgb = color.substr(color.indexOf("(") + 1).replace(")", "").split(",");
+      return "rgba(" + rgb[0] + "," + rgb[1] + "," + rgb[2] + "," + opacity + ")";
     } else {
       var rgb = exports.hexToRGB(color);
       if (rgb == null) {
         return color;
       } else {
-        return 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + opacity + ')';
+        return "rgba(" + rgb.r + "," + rgb.g + "," + rgb.b + "," + opacity + ")";
       }
     }
   };
@@ -1086,7 +1086,7 @@ return /******/ (function(modules) { // webpackBootstrap
    * @constructor
    */
   exports.RGBToHex = function (red, green, blue) {
-    return '#' + ((1 << 24) + (red << 16) + (green << 8) + blue).toString(16).slice(1);
+    return "#" + ((1 << 24) + (red << 16) + (green << 8) + blue).toString(16).slice(1);
   };
 
   /**
@@ -1302,12 +1302,12 @@ return /******/ (function(modules) { // webpackBootstrap
   };
 
   exports.isValidRGB = function (rgb) {
-    rgb = rgb.replace(' ', '');
+    rgb = rgb.replace(" ", "");
     var isOk = /rgb\((\d{1,3}),(\d{1,3}),(\d{1,3})\)/i.test(rgb);
     return isOk;
   };
   exports.isValidRGBA = function (rgba) {
-    rgba = rgba.replace(' ', '');
+    rgba = rgba.replace(" ", "");
     var isOk = /rgba\((\d{1,3}),(\d{1,3}),(\d{1,3}),(.{1,3})\)/i.test(rgba);
     return isOk;
   };
@@ -1320,11 +1320,11 @@ return /******/ (function(modules) { // webpackBootstrap
    * @returns {*}
    */
   exports.selectiveBridgeObject = function (fields, referenceObject) {
-    if (typeof referenceObject == 'object') {
+    if (typeof referenceObject == "object") {
       var objectTo = Object.create(referenceObject);
       for (var i = 0; i < fields.length; i++) {
         if (referenceObject.hasOwnProperty(fields[i])) {
-          if (typeof referenceObject[fields[i]] == 'object') {
+          if (typeof referenceObject[fields[i]] == "object") {
             objectTo[fields[i]] = exports.bridgeObject(referenceObject[fields[i]]);
           }
         }
@@ -1343,11 +1343,11 @@ return /******/ (function(modules) { // webpackBootstrap
    * @returns {*}
    */
   exports.bridgeObject = function (referenceObject) {
-    if (typeof referenceObject == 'object') {
+    if (typeof referenceObject == "object") {
       var objectTo = Object.create(referenceObject);
       for (var i in referenceObject) {
         if (referenceObject.hasOwnProperty(i)) {
-          if (typeof referenceObject[i] == 'object') {
+          if (typeof referenceObject[i] == "object") {
             objectTo[i] = exports.bridgeObject(referenceObject[i]);
           }
         }
@@ -5137,21 +5137,21 @@ return /******/ (function(modules) { // webpackBootstrap
     var point;
     if (groupTemplate.style == 'circle') {
       point = exports.getSVGElement('circle', JSONcontainer, svgContainer);
-      point.setAttributeNS(null, 'cx', x);
-      point.setAttributeNS(null, 'cy', y);
-      point.setAttributeNS(null, 'r', 0.5 * groupTemplate.size);
+      point.setAttributeNS(null, "cx", x);
+      point.setAttributeNS(null, "cy", y);
+      point.setAttributeNS(null, "r", 0.5 * groupTemplate.size);
     } else {
       point = exports.getSVGElement('rect', JSONcontainer, svgContainer);
-      point.setAttributeNS(null, 'x', x - 0.5 * groupTemplate.size);
-      point.setAttributeNS(null, 'y', y - 0.5 * groupTemplate.size);
-      point.setAttributeNS(null, 'width', groupTemplate.size);
-      point.setAttributeNS(null, 'height', groupTemplate.size);
+      point.setAttributeNS(null, "x", x - 0.5 * groupTemplate.size);
+      point.setAttributeNS(null, "y", y - 0.5 * groupTemplate.size);
+      point.setAttributeNS(null, "width", groupTemplate.size);
+      point.setAttributeNS(null, "height", groupTemplate.size);
     }
 
     if (groupTemplate.styles !== undefined) {
-      point.setAttributeNS(null, 'style', groupTemplate.styles);
+      point.setAttributeNS(null, "style", groupTemplate.styles);
     }
-    point.setAttributeNS(null, 'class', groupTemplate.className + ' vis-point');
+    point.setAttributeNS(null, "class", groupTemplate.className + " vis-point");
     //handle label
 
     if (labelObj) {
@@ -5168,10 +5168,10 @@ return /******/ (function(modules) { // webpackBootstrap
       }
 
       if (labelObj.className) {
-        label.setAttributeNS(null, 'class', labelObj.className + ' vis-label');
+        label.setAttributeNS(null, "class", labelObj.className + " vis-label");
       }
-      label.setAttributeNS(null, 'x', x);
-      label.setAttributeNS(null, 'y', y);
+      label.setAttributeNS(null, "x", x);
+      label.setAttributeNS(null, "y", y);
     }
 
     return point;
@@ -5191,13 +5191,13 @@ return /******/ (function(modules) { // webpackBootstrap
         y -= height;
       }
       var rect = exports.getSVGElement('rect', JSONcontainer, svgContainer);
-      rect.setAttributeNS(null, 'x', x - 0.5 * width);
-      rect.setAttributeNS(null, 'y', y);
-      rect.setAttributeNS(null, 'width', width);
-      rect.setAttributeNS(null, 'height', height);
-      rect.setAttributeNS(null, 'class', className);
+      rect.setAttributeNS(null, "x", x - 0.5 * width);
+      rect.setAttributeNS(null, "y", y);
+      rect.setAttributeNS(null, "width", width);
+      rect.setAttributeNS(null, "height", height);
+      rect.setAttributeNS(null, "class", className);
       if (style) {
-        rect.setAttributeNS(null, 'style', style);
+        rect.setAttributeNS(null, "style", style);
       }
     }
   };
@@ -5270,14 +5270,14 @@ return /******/ (function(modules) { // webpackBootstrap
     // all variants of a Date are internally stored as Date, so we can convert
     // from everything to everything (also from ISODate to Number for example)
     if (this._options.type) {
-      for (var field in this._options.type) {
-        if (this._options.type.hasOwnProperty(field)) {
-          var value = this._options.type[field];
-          if (value == 'Date' || value == 'ISODate' || value == 'ASPDate') {
-            this._type[field] = 'Date';
-          } else {
-            this._type[field] = value;
-          }
+      var fields = Object.keys(this._options.type);
+      for (var i = 0, len = fields.length; i < len; i++) {
+        var field = fields[i];
+        var value = this._options.type[field];
+        if (value == 'Date' || value == 'ISODate' || value == 'ASPDate') {
+          this._type[field] = 'Date';
+        } else {
+          this._type[field] = value;
         }
       }
     }
@@ -5394,7 +5394,7 @@ return /******/ (function(modules) { // webpackBootstrap
       subscribers = subscribers.concat(this._subscribers['*']);
     }
 
-    for (var i = 0; i < subscribers.length; i++) {
+    for (var i = 0, len = subscribers.length; i < len; i++) {
       var subscriber = subscribers[i];
       if (subscriber.callback) {
         subscriber.callback(event, params, senderId || null);
@@ -5544,6 +5544,7 @@ return /******/ (function(modules) { // webpackBootstrap
     var filter = options && options.filter;
     var items = [],
         item,
+        itemIds,
         itemId,
         i,
         len;
@@ -5565,12 +5566,12 @@ return /******/ (function(modules) { // webpackBootstrap
       }
     } else {
       // return all items
-      for (itemId in this._data) {
-        if (this._data.hasOwnProperty(itemId)) {
-          item = me._getItem(itemId, type);
-          if (!filter || filter(item)) {
-            items.push(item);
-          }
+      itemIds = Object.keys(this._data);
+      for (i = 0, len = itemIds.length; i < len; i++) {
+        itemId = itemIds[i];
+        item = me._getItem(itemId, type);
+        if (!filter || filter(item)) {
+          items.push(item);
         }
       }
     }
@@ -5594,9 +5595,11 @@ return /******/ (function(modules) { // webpackBootstrap
 
     // return the results
     if (returnType == 'Object') {
-      var result = {};
-      for (i = 0; i < items.length; i++) {
-        result[items[i].id] = items[i];
+      var result = {},
+          resultant;
+      for (i = 0, len = items.length; i < len; i++) {
+        resultant = items[i];
+        result[resultant.id] = resultant;
       }
       return result;
     } else {
@@ -5623,6 +5626,7 @@ return /******/ (function(modules) { // webpackBootstrap
         filter = options && options.filter,
         order = options && options.order,
         type = options && options.type || this._options.type,
+        itemIds = Object.keys(data),
         i,
         len,
         id,
@@ -5635,28 +5639,26 @@ return /******/ (function(modules) { // webpackBootstrap
       if (order) {
         // create ordered list
         items = [];
-        for (id in data) {
-          if (data.hasOwnProperty(id)) {
-            item = this._getItem(id, type);
-            if (filter(item)) {
-              items.push(item);
-            }
+        for (i = 0, len = itemIds.length; i < len; i++) {
+          id = itemIds[i];
+          item = this._getItem(id, type);
+          if (filter(item)) {
+            items.push(item);
           }
         }
 
         this._sort(items, order);
 
         for (i = 0, len = items.length; i < len; i++) {
-          ids[i] = items[i][this._fieldId];
+          ids.push(items[i][this._fieldId]);
         }
       } else {
         // create unordered list
-        for (id in data) {
-          if (data.hasOwnProperty(id)) {
-            item = this._getItem(id, type);
-            if (filter(item)) {
-              ids.push(item[this._fieldId]);
-            }
+        for (i = 0, len = itemIds.length; i < len; i++) {
+          id = itemIds[i];
+          item = this._getItem(id, type);
+          if (filter(item)) {
+            ids.push(item[this._fieldId]);
           }
         }
       }
@@ -5665,24 +5667,22 @@ return /******/ (function(modules) { // webpackBootstrap
       if (order) {
         // create an ordered list
         items = [];
-        for (id in data) {
-          if (data.hasOwnProperty(id)) {
-            items.push(data[id]);
-          }
+        for (i = 0, len = itemIds.length; i < len; i++) {
+          id = itemIds[i];
+          items.push(data[id]);
         }
 
         this._sort(items, order);
 
         for (i = 0, len = items.length; i < len; i++) {
-          ids[i] = items[i][this._fieldId];
+          ids.push(items[i][this._fieldId]);
         }
       } else {
         // create unordered list
-        for (id in data) {
-          if (data.hasOwnProperty(id)) {
-            item = data[id];
-            ids.push(item[this._fieldId]);
-          }
+        for (i = 0, len = itemIds.length; i < len; i++) {
+          id = itemIds[i];
+          item = data[id];
+          ids.push(item[this._fieldId]);
         }
       }
     }
@@ -5712,6 +5712,9 @@ return /******/ (function(modules) { // webpackBootstrap
     var filter = options && options.filter,
         type = options && options.type || this._options.type,
         data = this._data,
+        itemIds = Object.key(data),
+        i,
+        len,
         item,
         id;
 
@@ -5719,19 +5722,18 @@ return /******/ (function(modules) { // webpackBootstrap
       // execute forEach on ordered list
       var items = this.get(options);
 
-      for (var i = 0, len = items.length; i < len; i++) {
+      for (i = 0, len = items.length; i < len; i++) {
         item = items[i];
         id = item[this._fieldId];
         callback(item, id);
       }
     } else {
       // unordered
-      for (id in data) {
-        if (data.hasOwnProperty(id)) {
-          item = this._getItem(id, type);
-          if (!filter || filter(item)) {
-            callback(item, id);
-          }
+      for (i = 0, len = itemIds.length; i < len; i++) {
+        id = itemIds[i];
+        item = this._getItem(id, type);
+        if (!filter || filter(item)) {
+          callback(item, id);
         }
       }
     }
@@ -5753,15 +5755,18 @@ return /******/ (function(modules) { // webpackBootstrap
         type = options && options.type || this._options.type,
         mappedItems = [],
         data = this._data,
+        itemIds = Object.keys(data),
+        i,
+        len,
+        id,
         item;
 
     // convert and filter items
-    for (var id in data) {
-      if (data.hasOwnProperty(id)) {
-        item = this._getItem(id, type);
-        if (!filter || filter(item)) {
-          mappedItems.push(callback(item, id));
-        }
+    for (i = 0, len = itemIds.length; i < len; i++) {
+      id = itemIds[i];
+      item = this._getItem(id, type);
+      if (!filter || filter(item)) {
+        mappedItems.push(callback(item, id));
       }
     }
 
@@ -5786,17 +5791,23 @@ return /******/ (function(modules) { // webpackBootstrap
       return item;
     }
 
-    var filteredItem = {};
+    var filteredItem = {},
+        itemFields = Object.keys(item),
+        len = itemFields.length,
+        i,
+        field;
 
     if (Array.isArray(fields)) {
-      for (var field in item) {
-        if (item.hasOwnProperty(field) && fields.indexOf(field) != -1) {
+      for (i = 0; i < len; i++) {
+        field = itemFields[i];
+        if (fields.indexOf(field) != -1) {
           filteredItem[field] = item[field];
         }
       }
     } else {
-      for (var field in item) {
-        if (item.hasOwnProperty(field) && fields.hasOwnProperty(field)) {
+      for (i = 0; i < len; i++) {
+        field = itemFields[i];
+        if (fields.hasOwnProperty(field)) {
           filteredItem[fields[field]] = item[field];
         }
       }
@@ -5827,8 +5838,8 @@ return /******/ (function(modules) { // webpackBootstrap
     // TODO: extend order by an Object {field:String, direction:String}
     //       where direction can be 'asc' or 'desc'
     else {
-      throw new TypeError('Order must be a function or a string');
-    }
+        throw new TypeError('Order must be a function or a string');
+      }
   };
 
   /**
@@ -5912,17 +5923,19 @@ return /******/ (function(modules) { // webpackBootstrap
    */
   DataSet.prototype.max = function (field) {
     var data = this._data,
+        itemIds = Object.keys(data),
         max = null,
-        maxField = null;
+        maxField = null,
+        i,
+        len;
 
-    for (var id in data) {
-      if (data.hasOwnProperty(id)) {
-        var item = data[id];
-        var itemField = item[field];
-        if (itemField != null && (!max || itemField > maxField)) {
-          max = item;
-          maxField = itemField;
-        }
+    for (i = 0, len = itemIds.length; i < len; i++) {
+      var id = itemIds[i];
+      var item = data[id];
+      var itemField = item[field];
+      if (itemField != null && (!max || itemField > maxField)) {
+        max = item;
+        maxField = itemField;
       }
     }
 
@@ -5936,17 +5949,19 @@ return /******/ (function(modules) { // webpackBootstrap
    */
   DataSet.prototype.min = function (field) {
     var data = this._data,
+        itemIds = Object.keys(data),
         min = null,
-        minField = null;
+        minField = null,
+        i,
+        len;
 
-    for (var id in data) {
-      if (data.hasOwnProperty(id)) {
-        var item = data[id];
-        var itemField = item[field];
-        if (itemField != null && (!min || itemField < minField)) {
-          min = item;
-          minField = itemField;
-        }
+    for (i = 0, len = itemIds.length; i < len; i++) {
+      var id = itemIds[i];
+      var item = data[id];
+      var itemField = item[field];
+      if (itemField != null && (!min || itemField < minField)) {
+        min = item;
+        minField = itemField;
       }
     }
 
@@ -5962,31 +5977,31 @@ return /******/ (function(modules) { // webpackBootstrap
    */
   DataSet.prototype.distinct = function (field) {
     var data = this._data;
+    var itemIds = Object.keys(data);
     var values = [];
     var fieldType = this._options.type && this._options.type[field] || null;
     var count = 0;
-    var i;
-
-    for (var prop in data) {
-      if (data.hasOwnProperty(prop)) {
-        var item = data[prop];
-        var value = item[field];
-        var exists = false;
-        for (i = 0; i < count; i++) {
-          if (values[i] == value) {
-            exists = true;
-            break;
-          }
-        }
-        if (!exists && value !== undefined) {
-          values[count] = value;
-          count++;
+    var i, j, len;
+
+    for (i = 0, len = itemIds.length; i < len; i++) {
+      var id = itemIds[i];
+      var item = data[id];
+      var value = item[field];
+      var exists = false;
+      for (j = 0; j < count; j++) {
+        if (values[j] == value) {
+          exists = true;
+          break;
         }
       }
+      if (!exists && value !== undefined) {
+        values[count] = value;
+        count++;
+      }
     }
 
     if (fieldType) {
-      for (i = 0; i < values.length; i++) {
+      for (i = 0, len = values.length; i < len; i++) {
         values[i] = util.convert(values[i], fieldType);
       }
     }
@@ -6015,12 +6030,14 @@ return /******/ (function(modules) { // webpackBootstrap
       item[this._fieldId] = id;
     }
 
-    var d = {};
-    for (var field in item) {
-      if (item.hasOwnProperty(field)) {
-        var fieldType = this._type[field]; // type may be undefined
-        d[field] = util.convert(item[field], fieldType);
-      }
+    var d = {},
+        fields = Object.keys(item),
+        i,
+        len;
+    for (i = 0, len = fields.length; i < len; i++) {
+      var field = fields[i];
+      var fieldType = this._type[field]; // type may be undefined
+      d[field] = util.convert(item[field], fieldType);
     }
     this._data[id] = d;
     this.length++;
@@ -6036,7 +6053,7 @@ return /******/ (function(modules) { // webpackBootstrap
    * @private
    */
   DataSet.prototype._getItem = function (id, types) {
-    var field, value;
+    var field, value, i, len;
 
     // get the item from the dataset
     var raw = this._data[id];
@@ -6045,21 +6062,21 @@ return /******/ (function(modules) { // webpackBootstrap
     }
 
     // convert the items field types
-    var converted = {};
+    var converted = {},
+        fields = Object.keys(raw);
+
     if (types) {
-      for (field in raw) {
-        if (raw.hasOwnProperty(field)) {
-          value = raw[field];
-          converted[field] = util.convert(value, types[field]);
-        }
+      for (i = 0, len = fields.length; i < len; i++) {
+        field = fields[i];
+        value = raw[field];
+        converted[field] = util.convert(value, types[field]);
       }
     } else {
       // no field types specified, no converting needed
-      for (field in raw) {
-        if (raw.hasOwnProperty(field)) {
-          value = raw[field];
-          converted[field] = value;
-        }
+      for (i = 0, len = fields.length; i < len; i++) {
+        field = fields[i];
+        value = raw[field];
+        converted[field] = value;
       }
     }
     return converted;
@@ -6085,11 +6102,11 @@ return /******/ (function(modules) { // webpackBootstrap
     }
 
     // merge with current item
-    for (var field in item) {
-      if (item.hasOwnProperty(field)) {
-        var fieldType = this._type[field]; // type may be undefined
-        d[field] = util.convert(item[field], fieldType);
-      }
+    var fields = Object.keys(item);
+    for (var i = 0, len = fields.length; i < len; i++) {
+      var field = fields[i];
+      var fieldType = this._type[field]; // type may be undefined
+      d[field] = util.convert(item[field], fieldType);
     }
 
     return id;
@@ -6345,7 +6362,7 @@ return /******/ (function(modules) { // webpackBootstrap
    * @param {DataSet | DataView} data
    */
   DataView.prototype.setData = function (data) {
-    var ids, i, len;
+    var ids, id, i, len;
 
     if (this._data) {
       // unsubscribe from current dataset
@@ -6354,12 +6371,7 @@ return /******/ (function(modules) { // webpackBootstrap
       }
 
       // trigger a remove of all items in memory
-      ids = [];
-      for (var id in this._ids) {
-        if (this._ids.hasOwnProperty(id)) {
-          ids.push(id);
-        }
-      }
+      ids = Object.keys(this._ids);
       this._ids = {};
       this.length = 0;
       this._trigger('remove', { items: ids });
@@ -6392,34 +6404,34 @@ return /******/ (function(modules) { // webpackBootstrap
    * containing a variable parameter.
    */
   DataView.prototype.refresh = function () {
-    var id;
+    var id, i, len;
     var ids = this._data.getIds({ filter: this._options && this._options.filter });
+    var oldIds = Object.keys(this._ids);
     var newIds = {};
     var added = [];
     var removed = [];
 
     // check for additions
-    for (var i = 0; i < ids.length; i++) {
+    for (i = 0, len = ids.length; i < len; i++) {
       id = ids[i];
       newIds[id] = true;
       if (!this._ids[id]) {
         added.push(id);
         this._ids[id] = true;
-        this.length++;
       }
     }
 
     // check for removals
-    for (id in this._ids) {
-      if (this._ids.hasOwnProperty(id)) {
-        if (!newIds[id]) {
-          removed.push(id);
-          delete this._ids[id];
-          this.length--;
-        }
+    for (i = 0, len = oldIds.length; i < len; i++) {
+      id = oldIds[i];
+      if (!newIds[id]) {
+        removed.push(id);
+        delete this._ids[id];
       }
     }
 
+    this.length += added.length - removed.length;
+
     // trigger events
     if (added.length) {
       this._trigger('add', { items: added });
@@ -6604,7 +6616,9 @@ return /******/ (function(modules) { // webpackBootstrap
               if (this._ids[id]) {
                 delete this._ids[id];
                 removed.push(id);
-              } else {}
+              } else {
+                // nothing interesting for me :-(
+              }
             }
           }
 
@@ -6648,8 +6662,6 @@ return /******/ (function(modules) { // webpackBootstrap
 
   module.exports = DataView;
 
-  // nothing interesting for me :-(
-
 /***/ },
 /* 11 */
 /***/ function(module, exports, __webpack_require__) {
@@ -6893,9 +6905,11 @@ return /******/ (function(modules) { // webpackBootstrap
       if (backgroundColor.fill !== undefined) fill = backgroundColor.fill;
       if (backgroundColor.stroke !== undefined) stroke = backgroundColor.stroke;
       if (backgroundColor.strokeWidth !== undefined) strokeWidth = backgroundColor.strokeWidth;
-    } else if (backgroundColor === undefined) {} else {
-      throw 'Unsupported type of backgroundColor';
-    }
+    } else if (backgroundColor === undefined) {
+      // use use defaults
+    } else {
+        throw 'Unsupported type of backgroundColor';
+      }
 
     this.frame.style.backgroundColor = fill;
     this.frame.style.borderColor = stroke;
@@ -7601,9 +7615,9 @@ return /******/ (function(modules) { // webpackBootstrap
         widthMin = dotSize / 2; // px
         widthMax = dotSize / 2 + dotSize * 2; // Todo: put this in one function
       } else {
-        widthMin = 20; // px
-        widthMax = 20; // px
-      }
+          widthMin = 20; // px
+          widthMax = 20; // px
+        }
 
       var height = Math.max(this.frame.clientHeight * 0.25, 100);
       var top = this.margin;
@@ -8139,9 +8153,9 @@ return /******/ (function(modules) { // webpackBootstrap
               strokeStyle = this.axisColor; // TODO: should be customizable
             }
           } else {
-            fillStyle = 'gray';
-            strokeStyle = this.axisColor;
-          }
+              fillStyle = 'gray';
+              strokeStyle = this.axisColor;
+            }
 
           ctx.lineWidth = this._getStrokeWidth(point);
           ctx.fillStyle = fillStyle;
@@ -8157,39 +8171,39 @@ return /******/ (function(modules) { // webpackBootstrap
         }
       }
     } else {
-      // grid style
-      for (i = 0; i < this.dataPoints.length; i++) {
-        point = this.dataPoints[i];
-        right = this.dataPoints[i].pointRight;
-        top = this.dataPoints[i].pointTop;
+        // grid style
+        for (i = 0; i < this.dataPoints.length; i++) {
+          point = this.dataPoints[i];
+          right = this.dataPoints[i].pointRight;
+          top = this.dataPoints[i].pointTop;
 
-        if (point !== undefined && right !== undefined) {
-          // calculate Hue from the current value. At zMin the hue is 240, at zMax the hue is 0
-          zAvg = (point.point.z + right.point.z) / 2;
-          h = (1 - (zAvg - this.zMin) * this.scale.z / this.verticalRatio) * 240;
+          if (point !== undefined && right !== undefined) {
+            // calculate Hue from the current value. At zMin the hue is 240, at zMax the hue is 0
+            zAvg = (point.point.z + right.point.z) / 2;
+            h = (1 - (zAvg - this.zMin) * this.scale.z / this.verticalRatio) * 240;
 
-          ctx.lineWidth = this._getStrokeWidth(point) * 2;
-          ctx.strokeStyle = this._hsv2rgb(h, 1, 1);
-          ctx.beginPath();
-          ctx.moveTo(point.screen.x, point.screen.y);
-          ctx.lineTo(right.screen.x, right.screen.y);
-          ctx.stroke();
-        }
+            ctx.lineWidth = this._getStrokeWidth(point) * 2;
+            ctx.strokeStyle = this._hsv2rgb(h, 1, 1);
+            ctx.beginPath();
+            ctx.moveTo(point.screen.x, point.screen.y);
+            ctx.lineTo(right.screen.x, right.screen.y);
+            ctx.stroke();
+          }
 
-        if (point !== undefined && top !== undefined) {
-          // calculate Hue from the current value. At zMin the hue is 240, at zMax the hue is 0
-          zAvg = (point.point.z + top.point.z) / 2;
-          h = (1 - (zAvg - this.zMin) * this.scale.z / this.verticalRatio) * 240;
+          if (point !== undefined && top !== undefined) {
+            // calculate Hue from the current value. At zMin the hue is 240, at zMax the hue is 0
+            zAvg = (point.point.z + top.point.z) / 2;
+            h = (1 - (zAvg - this.zMin) * this.scale.z / this.verticalRatio) * 240;
 
-          ctx.lineWidth = this._getStrokeWidth(point) * 2;
-          ctx.strokeStyle = this._hsv2rgb(h, 1, 1);
-          ctx.beginPath();
-          ctx.moveTo(point.screen.x, point.screen.y);
-          ctx.lineTo(top.screen.x, top.screen.y);
-          ctx.stroke();
+            ctx.lineWidth = this._getStrokeWidth(point) * 2;
+            ctx.strokeStyle = this._hsv2rgb(h, 1, 1);
+            ctx.beginPath();
+            ctx.moveTo(point.screen.x, point.screen.y);
+            ctx.lineTo(top.screen.x, top.screen.y);
+            ctx.stroke();
+          }
         }
       }
-    }
   };
 
   Graph3d.prototype._getStrokeWidth = function (point) {
@@ -8896,8 +8910,6 @@ return /******/ (function(modules) { // webpackBootstrap
 
   module.exports = Graph3d;
 
-  // use use defaults
-
 /***/ },
 /* 12 */
 /***/ function(module, exports) {
@@ -10416,7 +10428,10 @@ return /******/ (function(modules) { // webpackBootstrap
         var getEnd = function getEnd(item) {
           var end = item.data.end != undefined ? item.data.end : item.data.start;
           return util.convert(end, 'Date').valueOf();
-        };
+        }
+
+        // calculate the date of the left side and right side of the items given
+        ;
 
         interval = max - min;
         // ms
@@ -10424,8 +10439,6 @@ return /******/ (function(modules) { // webpackBootstrap
           interval = 10;
         }
         factor = interval / _this.props.center.width;
-
-        // calculate the date of the left side and right side of the items given
         util.forEach(_this.itemSet.items, (function (item) {
           item.show();
 
@@ -14086,7 +14099,9 @@ return /******/ (function(modules) { // webpackBootstrap
   /**
    * Destroy the component. Cleanup DOM and event listeners
    */
-  Component.prototype.destroy = function () {};
+  Component.prototype.destroy = function () {
+    // should be implemented by the component
+  };
 
   /**
    * Test whether the component is resized since the last time _isResized() was
@@ -14105,8 +14120,6 @@ return /******/ (function(modules) { // webpackBootstrap
 
   module.exports = Component;
 
-  // should be implemented by the component
-
 /***/ },
 /* 27 */
 /***/ function(module, exports) {
@@ -14189,16 +14202,16 @@ return /******/ (function(modules) { // webpackBootstrap
                 }
                 startDate.dayOfYear(start.dayOfYear());
                 startDate.year(start.year());
-                startDate.subtract(7, "days");
+                startDate.subtract(7, 'days');
 
                 endDate.dayOfYear(start.dayOfYear());
                 endDate.year(start.year());
-                endDate.subtract(7 - offset, "days");
+                endDate.subtract(7 - offset, 'days');
 
-                runUntil.add(1, "weeks");
+                runUntil.add(1, 'weeks');
                 break;
               case "weekly":
-                var dayOffset = endDate.diff(startDate, "days");
+                var dayOffset = endDate.diff(startDate, 'days');
                 var day = startDate.day();
 
                 // set the start date to the range.start
@@ -14210,12 +14223,12 @@ return /******/ (function(modules) { // webpackBootstrap
                 // force
                 startDate.day(day);
                 endDate.day(day);
-                endDate.add(dayOffset, "days");
+                endDate.add(dayOffset, 'days');
 
-                startDate.subtract(1, "weeks");
-                endDate.subtract(1, "weeks");
+                startDate.subtract(1, 'weeks');
+                endDate.subtract(1, 'weeks');
 
-                runUntil.add(1, "weeks");
+                runUntil.add(1, 'weeks');
                 break;
               case "monthly":
                 if (startDate.month() != endDate.month()) {
@@ -14223,26 +14236,26 @@ return /******/ (function(modules) { // webpackBootstrap
                 }
                 startDate.month(start.month());
                 startDate.year(start.year());
-                startDate.subtract(1, "months");
+                startDate.subtract(1, 'months');
 
                 endDate.month(start.month());
                 endDate.year(start.year());
-                endDate.subtract(1, "months");
-                endDate.add(offset, "months");
+                endDate.subtract(1, 'months');
+                endDate.add(offset, 'months');
 
-                runUntil.add(1, "months");
+                runUntil.add(1, 'months');
                 break;
               case "yearly":
                 if (startDate.year() != endDate.year()) {
                   offset = 1;
                 }
                 startDate.year(start.year());
-                startDate.subtract(1, "years");
+                startDate.subtract(1, 'years');
                 endDate.year(start.year());
-                endDate.subtract(1, "years");
-                endDate.add(offset, "years");
+                endDate.subtract(1, 'years');
+                endDate.add(offset, 'years');
 
-                runUntil.add(1, "years");
+                runUntil.add(1, 'years');
                 break;
               default:
                 console.log("Wrong repeat format, allowed are: daily, weekly, monthly, yearly. Given:", hiddenDates[i].repeat);
@@ -14252,20 +14265,20 @@ return /******/ (function(modules) { // webpackBootstrap
               body.hiddenDates.push({ start: startDate.valueOf(), end: endDate.valueOf() });
               switch (hiddenDates[i].repeat) {
                 case "daily":
-                  startDate.add(1, "days");
-                  endDate.add(1, "days");
+                  startDate.add(1, 'days');
+                  endDate.add(1, 'days');
                   break;
                 case "weekly":
-                  startDate.add(1, "weeks");
-                  endDate.add(1, "weeks");
+                  startDate.add(1, 'weeks');
+                  endDate.add(1, 'weeks');
                   break;
                 case "monthly":
-                  startDate.add(1, "months");
-                  endDate.add(1, "months");
+                  startDate.add(1, 'months');
+                  endDate.add(1, 'months');
                   break;
                 case "yearly":
-                  startDate.add(1, "y");
-                  endDate.add(1, "y");
+                  startDate.add(1, 'y');
+                  endDate.add(1, 'y');
                   break;
                 default:
                   console.log("Wrong repeat format, allowed are: daily, weekly, monthly, yearly. Given:", hiddenDates[i].repeat);
@@ -14312,14 +14325,14 @@ return /******/ (function(modules) { // webpackBootstrap
           }
           // j start inside i
           else if (hiddenDates[j].start >= hiddenDates[i].start && hiddenDates[j].start <= hiddenDates[i].end) {
-            hiddenDates[i].end = hiddenDates[j].end;
-            hiddenDates[j].remove = true;
-          }
-          // j end inside i
-          else if (hiddenDates[j].end >= hiddenDates[i].start && hiddenDates[j].end <= hiddenDates[i].end) {
-            hiddenDates[i].start = hiddenDates[j].start;
-            hiddenDates[j].remove = true;
-          }
+              hiddenDates[i].end = hiddenDates[j].end;
+              hiddenDates[j].remove = true;
+            }
+            // j end inside i
+            else if (hiddenDates[j].end >= hiddenDates[i].start && hiddenDates[j].end <= hiddenDates[i].end) {
+                hiddenDates[i].start = hiddenDates[j].start;
+                hiddenDates[j].remove = true;
+              }
         }
       }
     }
@@ -15535,7 +15548,7 @@ return /******/ (function(modules) { // webpackBootstrap
 
     if (newScrollTop != oldScrollTop) {
       this._redraw(); // TODO: this causes two redraws when dragging, the other is triggered by rangechange already
-      this.emit('verticalDrag');
+      this.emit("verticalDrag");
     }
   };
 
@@ -15909,7 +15922,7 @@ return /******/ (function(modules) { // webpackBootstrap
   ItemSet.prototype.setOptions = function (options) {
     if (options) {
       // copy all options that we know
-      var fields = ['type', 'align', 'order', 'stack', 'selectable', 'multiselect', 'groupOrder', 'dataAttributes', 'template', 'groupTemplate', 'hide', 'snap', 'groupOrderSwap'];
+      var fields = ['type', 'align', 'order', 'stack', 'selectable', 'multiselect', 'multiselectPerGroup', 'groupOrder', 'dataAttributes', 'template', 'groupTemplate', 'hide', 'snap', 'groupOrderSwap'];
       util.selectiveExtend(fields, this.options, options);
 
       if ('orientation' in options) {
@@ -17121,25 +17134,25 @@ return /******/ (function(modules) { // webpackBootstrap
             }
             // if dragged group was move downwards everything above should have an offset
             else if (origOrder[curPos + orgOffset] == draggedId) {
-              orgOffset = 1;
-              continue;
-            }
-            // found a group (apart from dragged group) that has the wrong position -> switch with the
-            // group at the position where other one should be, fix index arrays and continue
-            else {
-              var slippedPosition = newOrder.indexOf(origOrder[curPos + orgOffset]);
-              var switchGroup = groupsData.get(newOrder[curPos + newOffset]);
-              var shouldBeGroup = groupsData.get(origOrder[curPos + orgOffset]);
-              this.options.groupOrderSwap(switchGroup, shouldBeGroup, groupsData);
-              groupsData.update(switchGroup);
-              groupsData.update(shouldBeGroup);
-
-              var switchGroupId = newOrder[curPos + newOffset];
-              newOrder[curPos + newOffset] = origOrder[curPos + orgOffset];
-              newOrder[slippedPosition] = switchGroupId;
-
-              curPos++;
-            }
+                orgOffset = 1;
+                continue;
+              }
+              // found a group (apart from dragged group) that has the wrong position -> switch with the
+              // group at the position where other one should be, fix index arrays and continue
+              else {
+                  var slippedPosition = newOrder.indexOf(origOrder[curPos + orgOffset]);
+                  var switchGroup = groupsData.get(newOrder[curPos + newOffset]);
+                  var shouldBeGroup = groupsData.get(origOrder[curPos + orgOffset]);
+                  this.options.groupOrderSwap(switchGroup, shouldBeGroup, groupsData);
+                  groupsData.update(switchGroup);
+                  groupsData.update(shouldBeGroup);
+
+                  var switchGroupId = newOrder[curPos + newOffset];
+                  newOrder[curPos + newOffset] = origOrder[curPos + orgOffset];
+                  newOrder[slippedPosition] = switchGroupId;
+
+                  curPos++;
+                }
           }
         }
       }
@@ -17321,35 +17334,48 @@ return /******/ (function(modules) { // webpackBootstrap
 
       if (shiftKey && this.options.multiselect) {
         // select all items between the old selection and the tapped item
+        var itemGroup = this.itemsData.get(item.id).group;
+
+        // when filtering get the group of the last selected item
+        var lastSelectedGroup = undefined;
+        if (this.options.multiselectPerGroup) {
+          if (selection.length > 0) {
+            lastSelectedGroup = this.itemsData.get(selection[0]).group;
+          }
+        }
 
         // determine the selection range
-        selection.push(item.id);
+        if (!this.options.multiselectPerGroup || lastSelectedGroup == undefined || lastSelectedGroup == itemGroup) {
+          selection.push(item.id);
+        }
         var range = ItemSet._getItemRange(this.itemsData.get(selection, this.itemOptions));
 
-        // select all items within the selection range
-        selection = [];
-        for (var id in this.items) {
-          if (this.items.hasOwnProperty(id)) {
-            var _item = this.items[id];
-            var start = _item.data.start;
-            var end = _item.data.end !== undefined ? _item.data.end : start;
-
-            if (start >= range.min && end <= range.max && !(_item instanceof BackgroundItem)) {
-              selection.push(_item.id); // do not use id but item.id, id itself is stringified
+        if (!this.options.multiselectPerGroup || lastSelectedGroup == itemGroup) {
+          // select all items within the selection range
+          selection = [];
+          for (var id in this.items) {
+            if (this.items.hasOwnProperty(id)) {
+              var _item = this.items[id];
+              var start = _item.data.start;
+              var end = _item.data.end !== undefined ? _item.data.end : start;
+
+              if (start >= range.min && end <= range.max && (!this.options.multiselectPerGroup || lastSelectedGroup == this.itemsData.get(_item.id).group) && !(_item instanceof BackgroundItem)) {
+                selection.push(_item.id); // do not use id but item.id, id itself is stringified
+              }
             }
           }
         }
       } else {
-        // add/remove this item from the current selection
-        var index = selection.indexOf(item.id);
-        if (index == -1) {
-          // item is not yet selected -> select it
-          selection.push(item.id);
-        } else {
-          // item is already selected -> deselect it
-          selection.splice(index, 1);
+          // add/remove this item from the current selection
+          var index = selection.indexOf(item.id);
+          if (index == -1) {
+            // item is not yet selected -> select it
+            selection.push(item.id);
+          } else {
+            // item is already selected -> deselect it
+            selection.splice(index, 1);
+          }
         }
-      }
 
       this.setSelection(selection);
 
@@ -17615,7 +17641,7 @@ return /******/ (function(modules) { // webpackBootstrap
    */
   TimeStep.prototype.setRange = function (start, end, minimumStep) {
     if (!(start instanceof Date) || !(end instanceof Date)) {
-      throw 'No legal start or end date in method setRange';
+      throw "No legal start or end date in method setRange";
     }
 
     this._start = start != undefined ? this.moment(start.valueOf()) : new Date();
@@ -17657,7 +17683,7 @@ return /******/ (function(modules) { // webpackBootstrap
         this.current.seconds(0);
       case 'second':
         this.current.milliseconds(0);
-        //case 'millisecond': // nothing to do for milliseconds
+      //case 'millisecond': // nothing to do for milliseconds
     }
 
     if (this.step != 1) {
@@ -17950,8 +17976,8 @@ return /******/ (function(modules) { // webpackBootstrap
         clone.add(1, 'month');
         // important: first set Date to 1, after that change the month.
       } else {
-        clone.date(1);
-      }
+          clone.date(1);
+        }
 
       clone.hours(0);
       clone.minutes(0);
@@ -18238,7 +18264,7 @@ return /******/ (function(modules) { // webpackBootstrap
     };
     this.checkRangedItems = false; // needed to refresh the ranged items if the window is programatically changed with NO overlap.
     var me = this;
-    this.itemSet.body.emitter.on('checkRangedItems', function () {
+    this.itemSet.body.emitter.on("checkRangedItems", function () {
       me.checkRangedItems = true;
     });
 
@@ -19127,10 +19153,10 @@ return /******/ (function(modules) { // webpackBootstrap
       //       a width which will not change when moving the Timeline
       //       So no re-stacking needed, which is nicer for the eye;
     } else {
-      this.left = start;
-      this.width = boxWidth;
-      contentWidth = Math.min(end - start, this.props.content.width);
-    }
+        this.left = start;
+        this.width = boxWidth;
+        contentWidth = Math.min(end - start, this.props.content.width);
+      }
 
     this.dom.box.style.left = this.left + 'px';
     this.dom.box.style.width = boxWidth + 'px';
@@ -19158,12 +19184,12 @@ return /******/ (function(modules) { // webpackBootstrap
             contentLeft = -contentWidth; // ensure it's not visible anymore
           }
         } else {
-          if (start < 0) {
-            contentLeft = -start;
-          } else {
-            contentLeft = 0;
+            if (start < 0) {
+              contentLeft = -start;
+            } else {
+              contentLeft = 0;
+            }
           }
-        }
         this.dom.content.style.left = contentLeft + 'px';
     }
   };
@@ -19355,17 +19381,23 @@ return /******/ (function(modules) { // webpackBootstrap
   /**
    * Repaint the item
    */
-  Item.prototype.redraw = function () {};
+  Item.prototype.redraw = function () {
+    // should be implemented by the item
+  };
 
   /**
    * Reposition the Item horizontally
    */
-  Item.prototype.repositionX = function () {};
+  Item.prototype.repositionX = function () {
+    // should be implemented by the item
+  };
 
   /**
    * Reposition the Item vertically
    */
-  Item.pr