diff --git a/Editor/ClusterViewer.cs b/Editor/ClusterViewer.cs
index e34e63f..925cfb0 100644
--- a/Editor/ClusterViewer.cs
+++ b/Editor/ClusterViewer.cs
@@ -58,7 +58,6 @@ namespace NanoBrain {
                     outputsPopup.RegisterValueChangedCallback(evt => OnOutputChanged(evt.newValue));
                     topMenuContainer.Add(outputsPopup);
                 }
-                Add(topMenuContainer);
 
                 scrollView = new(ScrollViewMode.Horizontal);
                 scrollView.style.position = Position.Absolute;
@@ -80,6 +79,7 @@ namespace NanoBrain {
 
                 scrollView.contentContainer.Add(graphContainer);
                 Add(scrollView);
+                Add(topMenuContainer);
 
 
                 // Subscribe when added to panel (editor UI ready)
@@ -437,17 +437,21 @@ namespace NanoBrain {
                 // This is used to 'scale' the output value colors of the nuclei
                 float maxValue = 0;
                 int neuronCount = 0;
-                List<Nucleus[]> drawnArrays = new();
+                //List<Nucleus[]> drawnArrays = new();
+                Cluster[] drawnCluster = null;
                 foreach (Synapse synapse in nucleus.synapses) {
                     if (synapse.neuron == null)
                         continue;
 
                     if (synapse.neuron.parent is Cluster cluster &&
-                        cluster.siblingClusters != null &&
+                        //cluster.siblingClusters != null &&
                         synapse.neuron.parent != nucleus.parent) {
-                        if (drawnArrays.Contains(cluster.siblingClusters))
+
+                        //if (drawnArrays.Contains(cluster.siblingClusters))
+                        if (drawnCluster is not null && cluster.SameSiblingsAs(drawnCluster))
                             continue;
-                        drawnArrays.Add(cluster.siblingClusters);
+                        //drawnArrays.Add(cluster.siblingClusters);
+                        drawnCluster = cluster.siblingClusters;
                     }
                     if (synapse.neuron is Neuron synapseNeuron) {
                         float value = synapseNeuron.outputMagnitude * synapse.weight;
@@ -463,25 +467,22 @@ namespace NanoBrain {
                 float margin = 10 + spacing / 2;
 
                 int row = 0;
-                drawnArrays = new();
+                //drawnArrays = new();
+                drawnCluster = null;
                 foreach (Synapse synapse in nucleus.synapses) {
                     if (synapse.neuron is null)
                         continue;
 
-                    // if (synapse.neuron is Receptor neuron) {
-                    //     if (drawnArrays.Contains(neuron.nucleiArray))
-                    //         continue;
-                    //     drawnArrays.Add(neuron.nucleiArray);
-                    // }
-                    // else if (synapse.neuron.parent is ClusterReceptor clusterReceptor) {
-                    //     if (drawnArrays.Contains(clusterReceptor.nucleiArray))
-                    //         continue;
-                    //     drawnArrays.Add(clusterReceptor.nucleiArray);
-                    // }
-                    if (synapse.neuron.parent is Cluster cluster) {
-                        if (drawnArrays.Contains(cluster.siblingClusters))
+                    if (synapse.neuron.parent is Cluster cluster && 
+                        //cluster.siblingClusters != null &&
+                        synapse.neuron.parent != nucleus.parent) {
+
+                        // if (drawnArrays.Contains(cluster.siblingClusters))
+                        //     continue;
+                        // drawnArrays.Add(cluster.siblingClusters);
+                        if (drawnCluster is not null && cluster.SameSiblingsAs(drawnCluster))
                             continue;
-                        drawnArrays.Add(cluster.siblingClusters);
+                        drawnCluster = cluster.siblingClusters;
                     }
                     Vector3 pos = new(250, margin + row * spacing, 0.0f);
                     Handles.color = Color.white;
@@ -547,7 +548,7 @@ namespace NanoBrain {
                     fontStyle = FontStyle.Bold,
                 };
 
-                if (nucleus.parent is Cluster parentCluster) {
+                if (nucleus.parent is Cluster parentCluster && parentCluster != currentNucleus.parent) {
                     if (expandArray) {
                         // Put array indices above elements
                         style.alignment = TextAnchor.LowerCenter;
diff --git a/Runtime/Scripts/Core/Cluster.cs b/Runtime/Scripts/Core/Cluster.cs
index 2482247..4159793 100644
--- a/Runtime/Scripts/Core/Cluster.cs
+++ b/Runtime/Scripts/Core/Cluster.cs
@@ -28,8 +28,6 @@ namespace NanoBrain {
             }
         }
 
-        //[SerializeReference]
-        //public ClusterArray clusterArray;
         [SerializeReference]
         public Cluster[] siblingClusters;
         public Dictionary<int, Cluster> thingClusters = new();
@@ -117,6 +115,44 @@ namespace NanoBrain {
                 }
             }
 
+            // Copy the siblings for clusters
+            for (int nucleusIx = 0; nucleusIx < prefabNuclei.Length; nucleusIx++) {
+                Nucleus prefabNucleus = prefabNuclei[nucleusIx];
+                if (prefabNucleus is not Cluster prefabCluster)
+                    continue;
+
+                if (prefabCluster.siblingClusters == null || prefabCluster.siblingClusters.Length == 0)
+                    continue;
+
+                Cluster clonedNucleus = clonedNuclei[nucleusIx] as Cluster;
+                if (prefabCluster == prefabCluster.siblingClusters[0]) {
+                    // We clone the array only for the first entry
+                    //NucleusArray clonedArray = new(prefabReceptor.nucleiArray.Length);
+                    Cluster[] clonedArray = new Cluster[prefabCluster.siblingClusters.Length];
+                    int arrayIx = 0;
+                    foreach (Cluster prefabArrayNucleus in prefabCluster.siblingClusters) {
+                        int arrayNucleusIx = GetNucleusIndex(prefabNuclei, prefabArrayNucleus);
+                        if (arrayNucleusIx >= 0) {
+                            Cluster clonedArrayNucleus = clonedNuclei[arrayNucleusIx] as Cluster;
+                            clonedArray[arrayIx] = clonedArrayNucleus;
+                        }
+                        else {
+                            Debug.LogError($" Could not find prefab nucleus {prefabNucleus.name} in the clones");
+                        }
+                        arrayIx++;
+                    }
+                    //clonedNucleus.array = clonedArray;
+                    clonedNucleus.siblingClusters = clonedArray;
+                }
+                else {
+                    // The others will refer to the array created for the first nucleus in the array
+                    int firstNucleusIx = GetNucleusIndex(prefabNuclei, prefabCluster.siblingClusters[0]);
+                    Cluster clonedFirstNucleus = clonedNuclei[firstNucleusIx] as Cluster;
+                    clonedNucleus.siblingClusters = clonedFirstNucleus.siblingClusters;
+                }
+            }
+
+
             foreach (Nucleus nucleus in this.clusterNuclei) {
                 if (nucleus is Cluster clonedSubCluster)
                     RestoreAllExternalReceivers(clonedSubCluster, this.prefab, this);
@@ -278,7 +314,6 @@ namespace NanoBrain {
 
         #region Cluster Array
 
-
         public void AddInstance(ClusterPrefab prefab) {
             // Ensure siblingClusters exists
             if (this.siblingClusters == null || this.siblingClusters.Length == 0)
@@ -366,6 +401,14 @@ namespace NanoBrain {
                 thingClusters.Remove(thingId);
         }
 
+        public bool SameSiblingsAs(Cluster[] otherSiblingClusters) {
+            for (int ix = 0; ix < this.siblingClusters.Length; ix++) {
+                if (this.siblingClusters[ix] != otherSiblingClusters[ix])
+                    return false;
+            }
+            return true;
+        }
+
         #endregion ClusterArray
 
         public ClusterPrefab prefab;