Got a Problem when serializing Class Dictionary with Custom Editor

Hi there. I've got so much frustation while using my Custom Editor.

first, I made a MagicInformation Class for my UI. it contains sprite and values for GUI. and also I used Dictionary for more comfortable management.

and I thought it'll be nice if I can serialize all of my Classes via Inspector. so I made a Custom Editor for UICore like this Sample Code. (sadly the Codes are not from myself, though.)

 using UnityEngine;
 using UnityEditor;
 using System.Collections.Generic;
 using System.Collections;
 
 [CustomEditor(typeof(UICore))]
 
 public class UICoreEditor : Editor {
     public bool Fold = false;
     public string Aditive_Key = "";
     public override void OnInspectorGUI()
     {
         base.OnInspectorGUI ();
         Aditive_Key = EditorGUILayout.TextField ("Input Key", Aditive_Key);
         Dictionary<string, MagicInformation> Dic = (target as UICore).MagicList;
 
         if (GUILayout.Button ("Add Data", GUILayout.Width (100))) {
             MagicInformation Data = new MagicInformation ();
 
             if (Dic.ContainsKey (Aditive_Key) == false)
                 Dic.Add (Aditive_Key, Data);
             else
                 EditorUtility.DisplayDialog ("Error", "Same Key Exists", "Close");
         }
 
         if (GUILayout.Button ("Delete Value", GUILayout.Width (100))) {
 
             if (Dic.ContainsKey (Aditive_Key) == true)
                 Dic.Remove (Aditive_Key);
             else
                 EditorUtility.DisplayDialog ("Error", "No Key Matched", "Close");
         }
 
         EditorGUILayout.Foldout (Fold, string.Format ("List({0})", Dic.Count));
         {
             foreach (var item in (target as UICore).MagicList) {
                 EditorGUILayout.LabelField (item.Key);
                 EditorGUILayout.BeginVertical ("Box");
                 item.Value.MagicImage = EditorGUILayout.ObjectField ("Sprite", item.Value.MagicImage, typeof(Sprite), false) as Sprite;
                 item.Value.MagicName = EditorGUILayout.TextField ("Magic Name", item.Value.MagicName);
                 item.Value.MagicCost = EditorGUILayout.IntField ("Magic Cost", item.Value.MagicCost);
                 item.Value.MagicDescription = EditorGUILayout.TextField ("Magic Description", item.Value.MagicDescription);
                 EditorGUILayout.EndVertical ();
             }
         }
     }
 }

and when I checked UICore I got this result.

It seemed works fine, but When I put my values and run a Game, I got an Error message "KeyNotFoundException: The given key was not present in the dictionary.". and all my values are gone from Inspector.

And I cannot even guess why this happens. I though "EditorGUILayout.Foldout()" function is enough for putting values for my dictionary, but there's no values. why this keeps happening?

please help me guys... my deadline is coming... :(