diff --git a/Assets/NatsunekoLaboratory/HierarchyStalker/Editor/HierarchyStalker.cs b/Assets/NatsunekoLaboratory/HierarchyStalker/Editor/HierarchyStalker.cs
index 8d6c617..764ac93 100644
--- a/Assets/NatsunekoLaboratory/HierarchyStalker/Editor/HierarchyStalker.cs
+++ b/Assets/NatsunekoLaboratory/HierarchyStalker/Editor/HierarchyStalker.cs
@@ -24,10 +24,10 @@ public class HierarchyStalker : EditorWindow
         private const string XamlGuid = "b7750c11aaa0c954ea1fa8f1b6490f5a";
 
         [SerializeField]
-        private List<Animation> _animations;
+        private List<Animation> _animations = new List<Animation>();
 
         [SerializeField] 
-        private List<AnimatorController> _controllers;
+        private List<AnimatorController> _controllers = new List<AnimatorController>();
 
         private bool _isTracking;
         private List<string> _selectionPaths;
diff --git a/Assets/NatsunekoLaboratory/HierarchyStalker/package.json b/Assets/NatsunekoLaboratory/HierarchyStalker/package.json
index 5844c3c..256a9dd 100644
--- a/Assets/NatsunekoLaboratory/HierarchyStalker/package.json
+++ b/Assets/NatsunekoLaboratory/HierarchyStalker/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cat.natsuneko.animation-auto-assignment",
-  "version": "0.3.1",
+  "version": "0.3.2",
   "displayName": "Animation Auto Assignment",
   "description": "Unity Editor Extension that tracks changes on hierarchy and automatically repairs animation property paths.",
   "unity": "2019.4",