diff --git a/src/game-lib-system-custom-code.js b/src/game-lib-system-custom-code.js
index afa99b7..23f0115 100644
--- a/src/game-lib-system-custom-code.js
+++ b/src/game-lib-system-custom-code.js
@@ -31,6 +31,15 @@ GameLib.System.CustomCode.prototype.start = function() {
 
     GameLib.System.prototype.start.call(this);
 
+    GameLib.EntityManager.Instance.queryComponents(GameLib.D3.CustomCode).map(
+        function(component) {
+            this.subscriptions[component.id] = GameLib.Event.Subscribe(
+                component.eventId,
+                component.instance
+            );
+        }.bind(this)
+    );
+
     this.instanceCreatedSubscription = GameLib.Event.Subscribe(
         GameLib.Event.INSTANCE_CREATED,
         this.instanceCreated.bind(this)
@@ -105,10 +114,25 @@ GameLib.System.CustomCode.prototype.stop = function() {
 
     GameLib.System.prototype.stop.call(this);
 
-    this.instanceCreatedSubscription.remove();
-    this.removeComponentSubscription.remove();
-    this.compileSuccessSubscription.remove();
-    this.compileFailedSubscription.remove();
+    if (this.instanceCreatedSubscription) {
+        this.instanceCreatedSubscription.remove();
+        this.instanceCreatedSubscription = null;
+    }
+
+    if (this.removeComponentSubscription) {
+        this.removeComponentSubscription.remove();
+        this.removeComponentSubscription = null;
+    }
+
+    if (this.compileSuccessSubscription) {
+        this.compileSuccessSubscription.remove();
+        this.compileSuccessSubscription = null;
+    }
+
+    if (this.compileFailedSubscription) {
+        this.compileFailedSubscription.remove();
+        this.compileFailedSubscription = null;
+    }
 
     Object.keys(this.subscriptions).map(
         function(componentId) {