diff --git a/Assets/Fungus/Editor/FungusScript/FungusScriptEditor.cs b/Assets/Fungus/Editor/FungusScript/FungusScriptEditor.cs
index 113677bc..6003b81c 100644
--- a/Assets/Fungus/Editor/FungusScript/FungusScriptEditor.cs
+++ b/Assets/Fungus/Editor/FungusScript/FungusScriptEditor.cs
@@ -11,16 +11,6 @@ namespace Fungus.Script
 	[CustomEditor (typeof(FungusScript))]
 	public class FungusScriptEditor : Editor 
 	{
-		SerializedProperty variablesProperty;
-		
-		void OnEnable() 
-		{
-			if (this != null && serializedObject != null)
-			{
-				variablesProperty = serializedObject.FindProperty("variables");
-			}
-		}
-		
 		public void OnInspectorUpdate()
 		{
 			Repaint();
@@ -28,8 +18,6 @@ namespace Fungus.Script
 		
 		public override void OnInspectorGUI() 
 		{
-			serializedObject.Update();
-			
 			FungusScript t = target as FungusScript;
 
 			if (t != null)
@@ -136,8 +124,6 @@ namespace Fungus.Script
 					DrawAddCommandGUI(t.selectedSequence);
 				}
 			}
-
-			serializedObject.ApplyModifiedProperties();
 		}
 
 		public void DrawSequenceGUI(Sequence sequence)
@@ -244,7 +230,8 @@ namespace Fungus.Script
 			FungusScript t = target as FungusScript;
 			
 			ReorderableListGUI.Title("Variables");
-			
+
+			SerializedProperty variablesProperty = serializedObject.FindProperty("variables");
 			FungusVariableListAdaptor adaptor = new FungusVariableListAdaptor(variablesProperty, 0);
 			ReorderableListControl.DrawControlFromState(adaptor, null, ReorderableListFlags.DisableContextMenu | ReorderableListFlags.HideAddButton);
 			
@@ -277,33 +264,9 @@ namespace Fungus.Script
 			
 			Undo.RecordObject(fungusScript, "Add Variable");
 			T variable = fungusScript.gameObject.AddComponent<T>();
-			variable.key = MakeUniqueKey(fungusScript);
+			variable.key = fungusScript.GetUniqueVariableKey("");
 			fungusScript.variables.Add(variable);
 		}
-
-		string MakeUniqueKey(FungusScript fungusScript)
-		{
-			int index = 0;
-			while (true)
-			{
-				string key = "Var" + index;
-				
-				bool found = false;
-				foreach(FungusVariable variable in fungusScript.GetComponents<FungusVariable>())
-				{
-					if (variable.key == key)
-					{
-						found = true;
-						index++;
-					}
-				}
-				
-				if (!found)
-				{
-					return key;
-				}
-			}
-		}
 	}
 	
 }
\ No newline at end of file
diff --git a/Assets/Fungus/Editor/FungusScript/FungusVariableListAdaptor.cs b/Assets/Fungus/Editor/FungusScript/FungusVariableListAdaptor.cs
index bc2f60fa..b20435a4 100644
--- a/Assets/Fungus/Editor/FungusScript/FungusVariableListAdaptor.cs
+++ b/Assets/Fungus/Editor/FungusScript/FungusVariableListAdaptor.cs
@@ -5,7 +5,6 @@
 using UnityEngine;
 using UnityEditor;
 using System;
-using System.Linq;
 using Rotorz.ReorderableList;
 
 namespace Fungus.Script
@@ -13,7 +12,7 @@ namespace Fungus.Script
 	public class FungusVariableListAdaptor : IReorderableListAdaptor {
 		
 		private SerializedProperty _arrayProperty;
-		
+
 		public float fixedItemHeight;
 		
 		public SerializedProperty this[int index] {
@@ -162,19 +161,18 @@ namespace Fungus.Script
 			}
 			
 			VariableScope scope = (VariableScope)EditorGUI.EnumPopup(scopeRect, variable.scope);
-			
+
+			FungusScript fungusScript = FungusScriptWindow.GetFungusScript();
+
 			if (EditorGUI.EndChangeCheck ())
 			{
 				Undo.RecordObject(variable, "Set Variable");
-				
-				char[] arr = key.Where(c => (char.IsLetterOrDigit(c) || c == '_')).ToArray(); 
-				key = new string(arr);
-				
-				variable.key = key;
+
+				// Modify the key if it clashes with an existing variable key
+				variable.key = fungusScript.GetUniqueVariableKey(key, variable);
 				variable.scope = scope;
 			}
 
-			FungusScript fungusScript = FungusScriptWindow.GetFungusScript();
 			if (fungusScript != null)
 			{
 				bool highlight = false;
diff --git a/Assets/Fungus/VisualScripting/FungusScript.cs b/Assets/Fungus/VisualScripting/FungusScript.cs
index d16f2e7a..cb8372ef 100644
--- a/Assets/Fungus/VisualScripting/FungusScript.cs
+++ b/Assets/Fungus/VisualScripting/FungusScript.cs
@@ -1,8 +1,6 @@
-#if UNITY_EDITOR
-using UnityEditor;
-#endif
-using UnityEngine;
+using UnityEngine;
 using System;
+using System.Linq;
 using System.Collections;
 using System.Collections.Generic;
 
@@ -73,6 +71,50 @@ namespace Fungus.Script
 			selectedSequence = sequence;
 			sequence.ExecuteNextCommand();
 		}
+
+		public string GetUniqueVariableKey(string originalKey, FungusVariable ignoreVariable = null)
+		{
+			int suffix = 0;
+			string baseKey = originalKey;
+
+			// Only letters and digits allowed
+			char[] arr = baseKey.Where(c => (char.IsLetterOrDigit(c) || c == '_')).ToArray(); 
+			baseKey = new string(arr);
+
+			// No leading digits allowed
+			baseKey = baseKey.TrimStart('0','1','2','3','4','5','6','7','8','9');
+
+			// No empty keys allowed
+			if (baseKey.Length == 0)
+			{
+				baseKey = "Var";
+			}
+
+			string key = baseKey;
+			while (true)
+			{
+				bool collision = false;
+				foreach(FungusVariable variable in GetComponents<FungusVariable>())
+				{
+					if (variable == ignoreVariable)
+					{
+						continue;
+					}
+
+					if (variable.key.Equals(key, StringComparison.CurrentCultureIgnoreCase))
+					{
+						collision = true;
+						suffix++;
+						key = baseKey + suffix;
+					}
+				}
+				
+				if (!collision)
+				{
+					return key;
+				}
+			}
+		}
 	}
 
 }
\ No newline at end of file
diff --git a/Assets/Shuttle/ShuttleGame.unity b/Assets/Shuttle/ShuttleGame.unity
index 3c9f6069..e43a687f 100644
Binary files a/Assets/Shuttle/ShuttleGame.unity and b/Assets/Shuttle/ShuttleGame.unity differ