diff --git a/examples/network/39_newClustering.html b/examples/network/39_newClustering.html
index c1eb3170..4de947aa 100644
--- a/examples/network/39_newClustering.html
+++ b/examples/network/39_newClustering.html
@@ -63,7 +63,7 @@
       processClusterProperties: function (properties, childNodes, childEdges) {
           return properties;
       },
-//      clusterNodeProperties: {id:'bla', borderWidth:8},
+      clusterNodeProperties: {id:'bla', borderWidth:8},
   }
 
   var clusterOptionsByData = {
@@ -73,7 +73,7 @@
       processClusterProperties: function (properties, childNodes, childEdges) {
           return properties;
       },
-//      clusterNodeProperties: {id:'bla', borderWidth:8}
+      clusterNodeProperties: {id:'bla', borderWidth:8}
   }
 
 //  network.clusterByNodeData(clusterOptionsByData)
@@ -89,7 +89,7 @@
 //  });
     network.on("select", function(params) {
         if (params.nodes.length == 1) {
-            if (params.nodes[0].indexOf("cluster") != -1) {
+            if (network.isCluster(params.nodes[0]) == true) {
                 network.openCluster(params.nodes[0])
             }
         }
diff --git a/lib/network/mixins/ClusterMixin.js b/lib/network/mixins/ClusterMixin.js
index 95359b2d..bf5fde36 100644
--- a/lib/network/mixins/ClusterMixin.js
+++ b/lib/network/mixins/ClusterMixin.js
@@ -94,7 +94,9 @@ exports.clusterOutliers = function(options, doNotUpdateCalculationNodes) {
     this._cluster(clusters[i].nodes, clusters[i].edges, options, true)
   }
 
-  this._wrapUp();
+  if (doNotUpdateCalculationNodes !== true) {
+    this._wrapUp();
+  }
 }
 
 /**
@@ -114,17 +116,15 @@ exports.clusterByConnection = function(nodeId, options, doNotUpdateCalculationNo
   if (options.clusterNodeProperties.y === undefined)  {options.clusterNodeProperties.y = node.y; options.clusterNodeProperties.allowedToMoveY = !node.yFixed;}
 
   var childNodesObj = {};
-  var edge;
   var childEdgesObj = {}
-  var childNodeId;
   var parentNodeId = node.id;
   var parentClonedOptions = this._cloneOptions(parentNodeId);
   childNodesObj[parentNodeId] = node;
 
   // collect the nodes that will be in the cluster
   for (var i = 0; i < node.edges.length; i++) {
-    edge = node.edges[i];
-    childNodeId = this._getConnectedId(edge, parentNodeId);
+    var edge = node.edges[i];
+    var childNodeId = this._getConnectedId(edge, parentNodeId);
 
     if (childNodeId !== parentNodeId) {
       if (options.joinCondition === undefined) {
@@ -148,6 +148,14 @@ exports.clusterByConnection = function(nodeId, options, doNotUpdateCalculationNo
   this._cluster(childNodesObj, childEdgesObj, options, doNotUpdateCalculationNodes);
 }
 
+
+/**
+ * This returns a clone of the options or properties of the edge or node to be used for construction of new edges or check functions for new nodes.
+ * @param objId
+ * @param type
+ * @returns {{}}
+ * @private
+ */
 exports._cloneOptions = function(objId, type) {
   var clonedOptions = {};
   if (type === undefined || type == 'node') {
@@ -161,6 +169,16 @@ exports._cloneOptions = function(objId, type) {
   return clonedOptions;
 }
 
+
+/**
+ * This function creates the edges that will be attached to the cluster.
+ *
+ * @param childNodesObj
+ * @param childEdgesObj
+ * @param newEdges
+ * @param options
+ * @private
+ */
 exports._createClusterEdges = function (childNodesObj, childEdgesObj, newEdges, options) {
   var edge, childNodeId, childNode;
 
@@ -209,12 +227,18 @@ exports._createClusterEdges = function (childNodesObj, childEdgesObj, newEdges,
 }
 
 
+/**
+ * This function checks the options that can be supplied to the different cluster functions
+ * for certain fields and inserts defaults if needed
+ * @param options
+ * @returns {*}
+ * @private
+ */
 exports._checkOptions = function(options) {
   if (options === undefined) {options = {};}
   if (options.clusterEdgeProperties === undefined)    {options.clusterEdgeProperties = {};}
   if (options.clusterNodeProperties === undefined)    {options.clusterNodeProperties = {};}
 
-
   return options;
 }
 
@@ -287,6 +311,7 @@ exports._cluster = function(childNodesObj, childEdgesObj, options, doNotUpdateCa
 
   // create the clusterNode
   var clusterNode = new Node(clusterNodeProperties, this.images, this.groups, this.constants);
+  clusterNode.isCluster = true;
   clusterNode.containedNodes = childNodesObj;
   clusterNode.containedEdges = childEdgesObj;
 
@@ -344,6 +369,22 @@ exports._cluster = function(childNodesObj, childEdgesObj, options, doNotUpdateCa
 }
 
 
+/**
+ * Check if a node is a cluster.
+ * @param nodeId
+ * @returns {*}
+ */
+exports.isCluster = function(nodeId) {
+  if (this.nodes[nodeId] !== undefined) {
+    return this.nodes[nodeId].isCluster;
+  }
+  else {
+    console.log("Node does not exist.")
+    return false;
+  }
+
+}
+
 /**
  * get the position of the cluster node based on what's inside
  * @param {object} childNodesObj    | object with node objects, id as keys
@@ -459,6 +500,11 @@ exports.openCluster = function(clusterNodeId, doNotUpdateCalculationNodes) {
   }
 }
 
+
+/**
+ * Recalculate navigation nodes, color edges dirty, update nodes list etc.
+ * @private
+ */
 exports._wrapUp = function() {
   this._updateNodeIndexList();
   this._updateCalculationNodes();
@@ -469,6 +515,15 @@ exports._wrapUp = function() {
   }
 }
 
+
+/**
+ * Connect an edge that was previously contained from cluster A to cluster B if the node that it was originally connected to
+ * is currently residing in cluster B
+ * @param edge
+ * @param nodeId
+ * @param from
+ * @private
+ */
 exports._connectEdge = function(edge, nodeId, from) {
   var clusterStack = this._getClusterStack(nodeId);
   if (from == true) {
@@ -486,6 +541,12 @@ exports._connectEdge = function(edge, nodeId, from) {
   edge.connect();
 }
 
+/**
+ * Get the stack clusterId's that a certain node resides in. cluster A -> cluster B -> cluster C -> node
+ * @param nodeId
+ * @returns {Array}
+ * @private
+ */
 exports._getClusterStack = function(nodeId) {
   var stack = [];
   var max = 100;
@@ -501,6 +562,13 @@ exports._getClusterStack = function(nodeId) {
 }
 
 
+/**
+ * Get the Id the node is connected to
+ * @param edge
+ * @param nodeId
+ * @returns {*}
+ * @private
+ */
 exports._getConnectedId = function(edge, nodeId) {
   if (edge.toId != nodeId) {
     return edge.toId;