diff --git a/HISTORY.md b/HISTORY.md
index a85d5dc2..99d814da 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -18,13 +18,20 @@ http://visjs.org
 
 ### Graph2d
 
-- Implemented a new option for `shaded.orientation` to always shade towards zero.
-  Thanks @ludost.
-- Fixed support for using a `DataView` in Graph2d. Thanks @ludost.
+- Large refactoring of Graph2d code base:
+  - Implemented a new option for `shaded.orientation` to always shade towards zero.
+  - Implemented a new option for `shaded.orientation` to follow another group (fill in between)
+  - Implemented line-graph stacking
+  - Fixed support for using a `DataView` in Graph2d.
+  - Implemented a new zindex option for controlling svg rendering order.
+  - Performance updates and fixes
 
 ### DataSet
 - Fixed #1487: DataSet cannot remove an item with id `0` correctly.
 
+### DataView
+- Added the map() function from DataSet.
+
 
 ## 2015-11-27, version 4.10.0
 
diff --git a/lib/DataView.js b/lib/DataView.js
index 7d5b2316..32a7325a 100644
--- a/lib/DataView.js
+++ b/lib/DataView.js
@@ -230,6 +230,49 @@ DataView.prototype.getIds = function (options) {
   return ids;
 };
 
+/**
+ * Map every item in the dataset.
+ * @param {function} callback
+ * @param {Object} [options]    Available options:
+ *                              {Object.<String, String>} [type]
+ *                              {String[]} [fields] filter fields
+ *                              {function} [filter] filter items
+ *                              {String | function} [order] Order the items by
+ *                                  a field name or custom sort function.
+ * @return {Object[]} mappedItems
+ */
+DataView.prototype.map = function (callback,options) {
+  var mappedItems = [];
+  if (this._data) {
+    var defaultFilter = this._options.filter;
+    var filter;
+
+    if (options && options.filter) {
+      if (defaultFilter) {
+        filter = function (item) {
+          return defaultFilter(item) && options.filter(item);
+        }
+      }
+      else {
+        filter = options.filter;
+      }
+    }
+    else {
+      filter = defaultFilter;
+    }
+
+    mappedItems = this._data.map(callback,{
+      filter: filter,
+      order: options && options.order
+    });
+  }
+  else {
+    mappedItems = [];
+  }
+
+  return mappedItems;
+};
+
 /**
  * Get the DataSet to which this DataView is connected. In case there is a chain
  * of multiple DataViews, the root DataSet of this chain is returned.
diff --git a/lib/timeline/component/DataAxis.js b/lib/timeline/component/DataAxis.js
index 02593649..4a1291a3 100644
--- a/lib/timeline/component/DataAxis.js
+++ b/lib/timeline/component/DataAxis.js
@@ -59,7 +59,7 @@ function DataAxis (body, options, svg, linegraphOptions) {
   this.setOptions(options);
   this.width = Number(('' + this.options.width).replace("px",""));
   this.minWidth = this.width;
-  this.height = this.linegraphSVG.offsetHeight;
+  this.height = this.linegraphSVG.getBoundingClientRect().height;
   this.hidden = false;
 
   this.stepPixels = 25;
diff --git a/lib/timeline/component/GraphGroup.js b/lib/timeline/component/GraphGroup.js
index 37917fc3..289c4f00 100644
--- a/lib/timeline/component/GraphGroup.js
+++ b/lib/timeline/component/GraphGroup.js
@@ -16,7 +16,7 @@ var Points = require('./graph2d_types/points');
  */
 function GraphGroup(group, groupId, options, groupsUsingDefaultStyles) {
   this.id = groupId;
-  var fields = ['sampling', 'style', 'sort', 'yAxisOrientation', 'barChart', 'drawPoints', 'shaded', 'interpolation'];
+  var fields = ['sampling', 'style', 'sort', 'yAxisOrientation', 'barChart', 'drawPoints', 'shaded', 'interpolation', 'zIndex'];
   this.options = util.selectiveBridgeObject(fields, options);
   this.usingDefaultStyle = group.className === undefined;
   this.groupsUsingDefaultStyles = groupsUsingDefaultStyles;
@@ -29,17 +29,6 @@ function GraphGroup(group, groupId, options, groupsUsingDefaultStyles) {
   this.visible = group.visible === undefined ? true : group.visible;
 }
 
-function insertionSort (a,compare) {
-  for (var i = 0; i < a.length; i++) {
-    var k = a[i];
-    for (var j = i; j > 0 && compare(k,a[j - 1])<0; j--) {
-      a[j] = a[j - 1];
-    }
-    a[j] = k;
-  }
-  return a;
-}
-
 /**
  * this loads a reference to all items in this group into this group.
  * @param {array} items
@@ -48,7 +37,7 @@ GraphGroup.prototype.setItems = function (items) {
   if (items != null) {
     this.itemsData = items;
     if (this.options.sort == true) {
-      insertionSort(this.itemsData,function (a, b) {
+      util.insertSort(this.itemsData,function (a, b) {
         return a.x > b.x ? 1 : -1;
       });
     }
@@ -76,7 +65,7 @@ GraphGroup.prototype.setZeroPosition = function (pos) {
  */
 GraphGroup.prototype.setOptions = function (options) {
   if (options !== undefined) {
-    var fields = ['sampling', 'style', 'sort', 'yAxisOrientation', 'barChart', 'excludeFromLegend', 'excludeFromStacking'];
+    var fields = ['sampling', 'style', 'sort', 'yAxisOrientation', 'barChart', 'excludeFromLegend', 'excludeFromStacking', 'zIndex'];
     util.selectiveDeepExtend(fields, this.options, options);
 
     // if the group's drawPoints is a function delegate the callback to the onRender property
@@ -145,7 +134,8 @@ GraphGroup.prototype.getLegend = function (iconWidth, iconHeight, framework, x,
     case "line":
       Lines.drawIcon(this, x, y, iconWidth, iconHeight, framework);
       break;
-    case "points":
+    case "points": //explicit no break
+    case "point":
       Points.drawIcon(this, x, y, iconWidth, iconHeight, framework);
       break;
     case "bar":
diff --git a/lib/timeline/component/LineGraph.js b/lib/timeline/component/LineGraph.js
index edf29781..bfdbaeb2 100644
--- a/lib/timeline/component/LineGraph.js
+++ b/lib/timeline/component/LineGraph.js
@@ -312,7 +312,6 @@ LineGraph.prototype.setItems = function (items) {
     ids = this.itemsData.getIds();
     this._onAdd(ids);
   }
-  this.redraw(true);
 };
 
 
@@ -333,7 +332,9 @@ LineGraph.prototype.setGroups = function (groups) {
     // remove all drawn groups
     ids = this.groupsData.getIds();
     this.groupsData = null;
-    this._onRemoveGroups(ids); // note: this will cause a redraw
+    for (var i = 0; i < ids.length; i++) {
+      this._removeGroup(ids[i]);
+    }
   }
 
   // replace the dataset
@@ -358,7 +359,6 @@ LineGraph.prototype.setGroups = function (groups) {
     ids = this.groupsData.getIds();
     this._onAddGroups(ids);
   }
-  this._onUpdate();
 };
 
 LineGraph.prototype._onUpdate = function (ids) {
@@ -593,6 +593,31 @@ LineGraph.prototype.redraw = function (forceGraphUpdate) {
 };
 
 
+LineGraph.prototype._getSortedGroupIds = function(){
+  // getting group Ids
+  var grouplist = [];
+  for (var groupId in this.groups) {
+    if (this.groups.hasOwnProperty(groupId)) {
+      var group = this.groups[groupId];
+      if (group.visible == true && (this.options.groups.visibility[groupId] === undefined || this.options.groups.visibility[groupId] == true)) {
+        grouplist.push({id:groupId,zIndex:group.options.zIndex});
+      }
+    }
+  }
+  util.insertSort(grouplist,function(a,b){
+    var az = a.zIndex;
+    var bz = b.zIndex;
+    if (az === undefined) az=0;
+    if (bz === undefined) bz=0;
+    return az==bz? 0: (az<bz ? -1: 1);
+  });
+  var groupIds = new Array(grouplist.length);
+  for (var i=0; i< grouplist.length; i++){
+    groupIds[i] = grouplist[i].id;
+  }
+  return groupIds;
+}
+
 /**
  * Update and redraw the graph.
  *
@@ -609,15 +634,7 @@ LineGraph.prototype._updateGraph = function () {
     var maxDate = this.body.util.toGlobalTime(2 * this.body.domProps.root.width);
 
     // getting group Ids
-    var groupIds = [];
-    for (var groupId in this.groups) {
-      if (this.groups.hasOwnProperty(groupId)) {
-        group = this.groups[groupId];
-        if (group.visible == true && (this.options.groups.visibility[groupId] === undefined || this.options.groups.visibility[groupId] == true)) {
-          groupIds.push(groupId);
-        }
-      }
-    }
+    var groupIds = this._getSortedGroupIds();
     if (groupIds.length > 0) {
       var groupsData = {};
 
@@ -715,8 +732,10 @@ LineGraph.prototype._updateGraph = function () {
                 }
                 Lines.draw(paths[groupIds[i]], group, this.framework);
               //explicit no break;
+              case "point":
+              //explicit no break;
               case "points":
-                if (group.options.style == "points" || group.options.drawPoints.enabled == true) {
+                if (group.options.style == "point" || group.options.style == "points" || group.options.drawPoints.enabled == true) {
                   Points.draw(groupsData[groupIds[i]], group, this.framework);
                 }
                 break;
diff --git a/lib/timeline/component/graph2d_types/bar.js b/lib/timeline/component/graph2d_types/bar.js
index 7b2e65f1..dfa688a6 100644
--- a/lib/timeline/component/graph2d_types/bar.js
+++ b/lib/timeline/component/graph2d_types/bar.js
@@ -16,6 +16,8 @@ Bargraph.drawIcon = function (group, x, y, iconWidth, iconHeight, framework) {
   outline.setAttributeNS(null, "class", "vis-outline");
 
   var barWidth = Math.round(0.3 * iconWidth);
+  var originalWidth = group.options.barChart.width;
+  var scale = originalWidth / barWidth;
   var bar1Height = Math.round(0.4 * iconHeight);
   var bar2Height = Math.round(0.75 * iconHeight);
 
@@ -28,7 +30,7 @@ Bargraph.drawIcon = function (group, x, y, iconWidth, iconHeight, framework) {
     var groupTemplate = {
       style: group.options.drawPoints.style,
       styles: group.options.drawPoints.styles,
-      size: Math.max(barWidth/5,group.options.drawPoints.size),
+      size: (group.options.drawPoints.size / scale),
       className: group.className
     };
     DOMutil.drawPoint(x + 0.5 * barWidth + offset, y + fillHeight - bar1Height - 1, groupTemplate, framework.svgElements, framework.svg);
@@ -49,7 +51,7 @@ Bargraph.draw = function (groupIds, processedGroupData, framework) {
   var coreDistance;
   var key, drawData;
   var group;
-  var i,j;
+  var i, j;
   var barPoints = 0;
 
   // combine all barchart data
@@ -61,6 +63,8 @@ Bargraph.draw = function (groupIds, processedGroupData, framework) {
           combinedData.push({
             screen_x: processedGroupData[groupIds[i]][j].screen_x,
             screen_y: processedGroupData[groupIds[i]][j].screen_y,
+            x: processedGroupData[groupIds[i]][j].x,
+            y: processedGroupData[groupIds[i]][j].y,
             groupId: groupIds[i],
             label: processedGroupData[groupIds[i]][j].label
           });
@@ -70,7 +74,9 @@ Bargraph.draw = function (groupIds, processedGroupData, framework) {
     }
   }
 
-  if (barPoints === 0) {return;}
+  if (barPoints === 0) {
+    return;
+  }
 
   // sort by time and by group
   combinedData.sort(function (a, b) {
@@ -93,15 +99,23 @@ Bargraph.draw = function (groupIds, processedGroupData, framework) {
     key = combinedData[i].screen_x;
     var heightOffset = 0;
     if (intersections[key] === undefined) {
-      if (i+1 < combinedData.length) {coreDistance = Math.abs(combinedData[i+1].screen_x - key);}
-      if (i > 0)                     {coreDistance = Math.min(coreDistance,Math.abs(combinedData[i-1].screen_x - key));}
+      if (i + 1 < combinedData.length) {
+        coreDistance = Math.abs(combinedData[i + 1].screen_x - key);
+      }
+      if (i > 0) {
+        coreDistance = Math.min(coreDistance, Math.abs(combinedData[i - 1].screen_x - key));
+      }
       drawData = Bargraph._getSafeDrawData(coreDistance, group, minWidth);
     }
     else {
       var nextKey = i + (intersections[key].amount - intersections[key].resolved);
       var prevKey = i - (intersections[key].resolved + 1);
-      if (nextKey < combinedData.length) {coreDistance = Math.abs(combinedData[nextKey].screen_x - key);}
-      if (prevKey > 0)                   {coreDistance = Math.min(coreDistance,Math.abs(combinedData[prevKey].screen_x - key));}
+      if (nextKey < combinedData.length) {
+        coreDistance = Math.abs(combinedData[nextKey].screen_x - key);
+      }
+      if (prevKey > 0) {
+        coreDistance = Math.min(coreDistance, Math.abs(combinedData[prevKey].screen_x - key));
+      }
       drawData = Bargraph._getSafeDrawData(coreDistance, group, minWidth);
       intersections[key].resolved += 1;
 
@@ -117,17 +131,23 @@ Bargraph.draw = function (groupIds, processedGroupData, framework) {
       }
       else if (group.options.barChart.sideBySide === true) {
         drawData.width = drawData.width / intersections[key].amount;
-        drawData.offset += (intersections[key].resolved) * drawData.width - (0.5*drawData.width * (intersections[key].amount+1));
-        if (group.options.barChart.align === 'left')       {drawData.offset -= 0.5*drawData.width;}
-        else if (group.options.barChart.align === 'right') {drawData.offset += 0.5*drawData.width;}
+        drawData.offset += (intersections[key].resolved) * drawData.width - (0.5 * drawData.width * (intersections[key].amount + 1));
+        if (group.options.barChart.align === 'left') {
+          drawData.offset -= 0.5 * drawData.width;
+        }
+        else if (group.options.barChart.align === 'right') {
+          drawData.offset += 0.5 * drawData.width;
+        }
       }
     }
     DOMutil.drawBar(combinedData[i].screen_x + drawData.offset, combinedData[i].screen_y - heightOffset, drawData.width, group.zeroPosition - combinedData[i].screen_y, group.className + ' vis-bar', framework.svgElements, framework.svg, group.style);
     // draw points
     if (group.options.drawPoints.enabled === true) {
       let pointData = {
-        screen_x:combinedData[i].screen_x,
-        screen_y:combinedData[i].screen_y - heightOffset,
+        screen_x: combinedData[i].screen_x,
+        screen_y: combinedData[i].screen_y - heightOffset,
+        x: combinedData[i].x,
+        y: combinedData[i].y,
         groupId: combinedData[i].groupId,
         label: combinedData[i].label
       };
@@ -156,7 +176,12 @@ Bargraph._getDataIntersections = function (intersections, combinedData) {
     }
     if (coreDistance === 0) {
       if (intersections[combinedData[i].screen_x] === undefined) {
-        intersections[combinedData[i].screen_x] = {amount: 0, resolved: 0, accumulatedPositive: 0, accumulatedNegative: 0};
+        intersections[combinedData[i].screen_x] = {
+          amount: 0,
+          resolved: 0,
+          accumulatedPositive: 0,
+          accumulatedNegative: 0
+        };
       }
       intersections[combinedData[i].screen_x].amount += 1;
     }
@@ -201,13 +226,13 @@ Bargraph._getSafeDrawData = function (coreDistance, group, minWidth) {
   return {width: width, offset: offset};
 };
 
-Bargraph.getStackedYRange = function(combinedData, groupRanges, groupIds, groupLabel, orientation) {
+Bargraph.getStackedYRange = function (combinedData, groupRanges, groupIds, groupLabel, orientation) {
   if (combinedData.length > 0) {
     // sort by time and by group
     combinedData.sort(function (a, b) {
       if (a.screen_x === b.screen_x) {
         return a.groupId < b.groupId ? -1 : 1;
-      } 
+      }
       else {
         return a.screen_x - b.screen_x;
       }
diff --git a/lib/timeline/component/graph2d_types/points.js b/lib/timeline/component/graph2d_types/points.js
index 4241b622..c6a05a92 100644
--- a/lib/timeline/component/graph2d_types/points.js
+++ b/lib/timeline/component/graph2d_types/points.js
@@ -66,7 +66,6 @@ function getCallback(framework, group) {
   if (group.group.options && group.group.options.drawPoints && group.group.options.drawPoints.onRender && typeof group.group.options.drawPoints.onRender == 'function') {
     callback = group.group.options.drawPoints.onRender;
   }
-
   return callback;
 }
 
diff --git a/lib/timeline/optionsGraph2d.js b/lib/timeline/optionsGraph2d.js
index 883c4da1..978624a2 100644
--- a/lib/timeline/optionsGraph2d.js
+++ b/lib/timeline/optionsGraph2d.js
@@ -162,6 +162,7 @@ let allOptions = {
   zoomKey: {string: ['ctrlKey', 'altKey', 'metaKey', '']},
   zoomMax: {number},
   zoomMin: {number},
+  zIndex: {number},
   __type__: {object}
 };
 
@@ -265,7 +266,8 @@ let configureOptions = {
     zoomable: true,
     zoomKey: ['ctrlKey', 'altKey', 'metaKey', ''],
     zoomMax: [315360000000000, 10, 315360000000000, 1],
-    zoomMin: [10, 10, 315360000000000, 1]
+    zoomMin: [10, 10, 315360000000000, 1],
+    zIndex: 0
   }
 };
 
diff --git a/lib/util.js b/lib/util.js
index 9b1999f0..8fac4aee 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -1253,6 +1253,23 @@ exports.bridgeObject = function (referenceObject) {
   }
 };
 
+/**
+ * This method provides a stable sort implementation, very fast for presorted data
+ *
+ * @param a the array
+ * @param a order comparator
+ * @returns {the array}
+ */
+exports.insertSort = function (a,compare) {
+  for (var i = 0; i < a.length; i++) {
+    var k = a[i];
+    for (var j = i; j > 0 && compare(k,a[j - 1])<0; j--) {
+      a[j] = a[j - 1];
+    }
+    a[j] = k;
+  }
+  return a;
+}
 
 /**
  * this is used to set the options of subobjects in the options object. A requirement of these subobjects