diff --git a/HISTORY.md b/HISTORY.md
index ed68c1e3..0545624d 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -15,6 +15,7 @@ http://visjs.org
 - Fixed #1588: destroy now unsubscribed from the dataset.
 - Fixed #1584: Navigation buttons broken.
 - Fixed #1596: correct clean up of manipulation dom elements.
+- Fixed #1594: bug in hierarchical layout.
 
 ### Timeline
 
diff --git a/dist/vis.js b/dist/vis.js
index 4d0e8453..a27be191 100644
--- a/dist/vis.js
+++ b/dist/vis.js
@@ -40206,7 +40206,7 @@ return /******/ (function(modules) { // webpackBootstrap
           // force all edges into static smooth curves. Only applies to edges that do not use the global options for smooth.
           this.body.emitter.emit('_forceDisableDynamicCurves', type);
         }
-        console.log(JSON.stringify(allOptions), JSON.stringify(this.optionsBackup));
+
         return allOptions;
       }
     }, {
@@ -40401,6 +40401,14 @@ return /******/ (function(modules) { // webpackBootstrap
               }
             }
 
+            // fallback for cases where there are nodes but no edges
+            for (var _nodeId in this.body.nodes) {
+              if (this.body.nodes.hasOwnProperty(_nodeId)) {
+                if (this.hierarchicalLevels[_nodeId] === undefined) {
+                  this.hierarchicalLevels[_nodeId] = 0;
+                }
+              }
+            }
             // check the distribution of the nodes per level.
             var distribution = this._getDistribution();
 
@@ -40466,7 +40474,7 @@ return /******/ (function(modules) { // webpackBootstrap
               }
             }
           }
-          return [min, max];
+          return { min: min, max: max };
         };
 
         // get the width of all trees
@@ -40856,27 +40864,31 @@ return /******/ (function(modules) { // webpackBootstrap
           useMap = false;
         }
         var level = this.hierarchicalLevels[node.id];
-        var index = this.distributionIndex[node.id];
-        var position = this._getPositionForHierarchy(node);
-        var minSpace = 1e9;
-        var maxSpace = 1e9;
-        if (index !== 0) {
-          var prevNode = this.distributionOrdering[level][index - 1];
-          if (useMap === true && map[prevNode.id] === undefined || useMap === false) {
-            var prevPos = this._getPositionForHierarchy(prevNode);
-            minSpace = position - prevPos;
+        if (level !== undefined) {
+          var index = this.distributionIndex[node.id];
+          var position = this._getPositionForHierarchy(node);
+          var minSpace = 1e9;
+          var maxSpace = 1e9;
+          if (index !== 0) {
+            var prevNode = this.distributionOrdering[level][index - 1];
+            if (useMap === true && map[prevNode.id] === undefined || useMap === false) {
+              var prevPos = this._getPositionForHierarchy(prevNode);
+              minSpace = position - prevPos;
+            }
           }
-        }
 
-        if (index != this.distributionOrdering[level].length - 1) {
-          var nextNode = this.distributionOrdering[level][index + 1];
-          if (useMap === true && map[nextNode.id] === undefined || useMap === false) {
-            var nextPos = this._getPositionForHierarchy(nextNode);
-            maxSpace = Math.min(maxSpace, nextPos - position);
+          if (index != this.distributionOrdering[level].length - 1) {
+            var nextNode = this.distributionOrdering[level][index + 1];
+            if (useMap === true && map[nextNode.id] === undefined || useMap === false) {
+              var nextPos = this._getPositionForHierarchy(nextNode);
+              maxSpace = Math.min(maxSpace, nextPos - position);
+            }
           }
-        }
 
-        return [minSpace, maxSpace];
+          return [minSpace, maxSpace];
+        } else {
+          return [0, 0];
+        }
       }
 
       /**
@@ -41134,14 +41146,18 @@ return /******/ (function(modules) { // webpackBootstrap
         // get the minimum level
         for (var nodeId in this.body.nodes) {
           if (this.body.nodes.hasOwnProperty(nodeId)) {
-            minLevel = Math.min(this.hierarchicalLevels[nodeId], minLevel);
+            if (this.hierarchicalLevels[nodeId] !== undefined) {
+              minLevel = Math.min(this.hierarchicalLevels[nodeId], minLevel);
+            }
           }
         }
 
         // subtract the minimum from the set so we have a range starting from 0
         for (var nodeId in this.body.nodes) {
           if (this.body.nodes.hasOwnProperty(nodeId)) {
-            this.hierarchicalLevels[nodeId] -= minLevel;
+            if (this.hierarchicalLevels[nodeId] !== undefined) {
+              this.hierarchicalLevels[nodeId] -= minLevel;
+            }
           }
         }
       }
@@ -41190,15 +41206,17 @@ return /******/ (function(modules) { // webpackBootstrap
             progress[node.id] = true;
             var childNode = undefined;
             for (var i = 0; i < node.edges.length; i++) {
-              if (node.edges[i].toId === node.id) {
-                childNode = node.edges[i].from;
-              } else {
-                childNode = node.edges[i].to;
-              }
+              if (node.edges[i].connected === true) {
+                if (node.edges[i].toId === node.id) {
+                  childNode = node.edges[i].from;
+                } else {
+                  childNode = node.edges[i].to;
+                }
 
-              if (node.id !== childNode.id) {
-                callback(node, childNode, node.edges[i]);
-                crawler(childNode);
+                if (node.id !== childNode.id) {
+                  callback(node, childNode, node.edges[i]);
+                  crawler(childNode);
+                }
               }
             }
           }
@@ -41402,6 +41420,7 @@ return /******/ (function(modules) { // webpackBootstrap
             }
           }
         }
+
         if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
           node.x = position;
         } else {
diff --git a/lib/network/modules/LayoutEngine.js b/lib/network/modules/LayoutEngine.js
index 6585483f..8e4fc6b3 100644
--- a/lib/network/modules/LayoutEngine.js
+++ b/lib/network/modules/LayoutEngine.js
@@ -148,7 +148,7 @@ class LayoutEngine {
       // force all edges into static smooth curves. Only applies to edges that do not use the global options for smooth.
       this.body.emitter.emit('_forceDisableDynamicCurves', type);
     }
-    console.log(JSON.stringify(allOptions), JSON.stringify(this.optionsBackup));
+
     return allOptions;
   }
 
@@ -339,6 +339,15 @@ class LayoutEngine {
           }
         }
 
+
+        // fallback for cases where there are nodes but no edges
+        for (let nodeId in this.body.nodes) {
+          if (this.body.nodes.hasOwnProperty(nodeId)) {
+            if (this.hierarchicalLevels[nodeId] === undefined) {
+              this.hierarchicalLevels[nodeId] = 0;
+            }
+          }
+        }
         // check the distribution of the nodes per level.
         let distribution = this._getDistribution();
 
@@ -400,7 +409,7 @@ class LayoutEngine {
           }
         }
       }
-      return [min, max];
+      return {min:min, max:max};
     };
 
     // get the width of all trees
@@ -751,27 +760,32 @@ class LayoutEngine {
       useMap = false;
     }
     let level = this.hierarchicalLevels[node.id];
-    let index = this.distributionIndex[node.id];
-    let position = this._getPositionForHierarchy(node);
-    let minSpace = 1e9;
-    let maxSpace = 1e9;
-    if (index !== 0) {
-      let prevNode = this.distributionOrdering[level][index - 1];
-      if ((useMap === true && map[prevNode.id] === undefined) || useMap === false) {
-        let prevPos = this._getPositionForHierarchy(prevNode);
-        minSpace = position - prevPos;
+    if (level !== undefined) {
+      let index = this.distributionIndex[node.id];
+      let position = this._getPositionForHierarchy(node);
+      let minSpace = 1e9;
+      let maxSpace = 1e9;
+      if (index !== 0) {
+        let prevNode = this.distributionOrdering[level][index - 1];
+        if ((useMap === true && map[prevNode.id] === undefined) || useMap === false) {
+          let prevPos = this._getPositionForHierarchy(prevNode);
+          minSpace = position - prevPos;
+        }
       }
-    }
 
-    if (index != this.distributionOrdering[level].length - 1) {
-      let nextNode = this.distributionOrdering[level][index + 1];
-      if ((useMap === true && map[nextNode.id] === undefined) || useMap === false) {
-        let nextPos = this._getPositionForHierarchy(nextNode);
-        maxSpace = Math.min(maxSpace, nextPos - position);
+      if (index != this.distributionOrdering[level].length - 1) {
+        let nextNode = this.distributionOrdering[level][index + 1];
+        if ((useMap === true && map[nextNode.id] === undefined) || useMap === false) {
+          let nextPos = this._getPositionForHierarchy(nextNode);
+          maxSpace = Math.min(maxSpace, nextPos - position);
+        }
       }
-    }
 
-    return [minSpace, maxSpace];
+      return [minSpace, maxSpace];
+    }
+    else {
+      return [0, 0];
+    }
   }
 
   /**
@@ -1007,14 +1021,18 @@ class LayoutEngine {
     // get the minimum level
     for (let nodeId in this.body.nodes) {
       if (this.body.nodes.hasOwnProperty(nodeId)) {
-        minLevel = Math.min(this.hierarchicalLevels[nodeId], minLevel);
+        if (this.hierarchicalLevels[nodeId] !== undefined) {
+          minLevel = Math.min(this.hierarchicalLevels[nodeId], minLevel);
+        }
       }
     }
 
     // subtract the minimum from the set so we have a range starting from 0
     for (let nodeId in this.body.nodes) {
       if (this.body.nodes.hasOwnProperty(nodeId)) {
-        this.hierarchicalLevels[nodeId] -= minLevel;
+        if (this.hierarchicalLevels[nodeId] !== undefined) {
+          this.hierarchicalLevels[nodeId] -= minLevel;
+        }
       }
     }
   }
@@ -1057,12 +1075,18 @@ class LayoutEngine {
         progress[node.id] = true;
         let childNode;
         for (let i = 0; i < node.edges.length; i++) {
-          if (node.edges[i].toId === node.id) {childNode = node.edges[i].from;}
-          else                                {childNode = node.edges[i].to;}
+          if (node.edges[i].connected === true) {
+            if (node.edges[i].toId === node.id) {
+              childNode = node.edges[i].from;
+            }
+            else {
+              childNode = node.edges[i].to;
+            }
 
-          if (node.id !== childNode.id) {
-            callback(node, childNode, node.edges[i]);
-            crawler(childNode);
+            if (node.id !== childNode.id) {
+              callback(node, childNode, node.edges[i]);
+              crawler(childNode);
+            }
           }
         }
       }
@@ -1259,6 +1283,7 @@ class LayoutEngine {
         }
       }
     }
+
     if (this.options.hierarchical.direction === 'UD' || this.options.hierarchical.direction === 'DU') {
       node.x = position;
     }