Question ScriptableSingleton<T> derived class showing gui as disabled in settings provider

ScriptableSingleton<T> derived class showing GUI as disabled when showing its properties in the settings provider. Works ok with normal scriptable objects. What is wrong with my implementation?
Unity Version: 2021.3.2f1

Code (CSharp):

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using UnityEditor;
5. using UnityEditor.Graphs;
6. using UnityEditor.UIElements;
7. using UnityEngine;
8. using UnityEngine.UIElements;
9.  
10. namespace RSS.Editor.Tools.Clipper
11. {
12.     [FilePath("ProjectSettings/Clipper.asset", FilePathAttribute.Location.ProjectFolder)]
13.     internal class ClipperSettings : ScriptableSingleton<ClipperSettings>
14.     {
15.         [SerializeField]
16.         private ClipDuplication clipDuplication;
17.         public ClipDuplication ClipDuplication
18.         {
19.             get { return clipDuplication; }
20.             set {
21.                 clipDuplication = value;
22.                 Save(true);
23.             }
24.         }
25.         [SerializeField]
26.         private bool autoDeletion;
27.         public bool AutoDeletion
28.         {
29.             get { return autoDeletion; }
30.             set
31.             {
32.                 autoDeletion = value;
33.                 Save(true);
34.             }
35.         }
36.         [SerializeField]
37.         private bool includeFavourites;
38.         public bool IncludeFavourites
39.         {
40.             get { return includeFavourites; }
41.             set
42.             {
43.                 includeFavourites = value;
44.                 Save(true);
45.             }
46.         }
47.         [SerializeField]
48.         private int daysBeforeDelete;
49.         public int DaysBeforeDelete
50.         {
51.             get { return daysBeforeDelete; }
52.             set
53.             {
54.                 DaysBeforeDelete = value;
55.                 Save(true);
56.             }
57.         }
58.         [SerializeField]
59.         private List<Clip> clips;
60.         public List<Clip> Clips
61.         {
62.             get { return clips; }
63.             set
64.             {
65.                 clips = value;
66.                 Save(true);
67.             }
68.         }
69.         public const string VERSION = "1.0.0";
70.  
71.  
72.         [InitializeOnLoadMethod]
73.         private static void OnCompile()
74.         {
75.             if(instance.AutoDeletion)
76.             {
77.                 var clipsToDelete = instance.Clips.Where(c => DateTime.Now.Subtract(DateTime.FromBinary(c.createdAt)).TotalDays >= instance.DaysBeforeDelete);
78.                 foreach (var clip in clipsToDelete)
79.                 {
80.                     if (!instance.IncludeFavourites && clip.IsFavourite) continue;
81.                     instance.Clips.Remove(clip);
82.                 }
83.             };
84.  
85.             Save();
86.         }
87.  
88.         public static void Save()
89.         {
90.             instance.Save(true);
91.         }
92.  
93.         internal static SerializedObject GetSerializedSettings()
94.         {
95.             return new SerializedObject(instance);
96.         }
97.     }
98.     internal class ClipperSettingsProvider : SettingsProvider
99.     {
100.         private const string SettingsPath = "Project/Rocketshift Studio/Clipper";
101.         SerializedObject serializedObject;
102.         SerializedProperty clipDuplication;
103.         SerializedProperty autoDeletion;
104.         SerializedProperty includeFavourites;
105.         SerializedProperty daysBeforeDelete;
106.         SerializedProperty clips;
107.  
108.         public ClipperSettingsProvider(string path, SettingsScope scopes, IEnumerable<string> keywords = null) : base(path, scopes, keywords)
109.         {
110.         }
111.  
112.         public static bool IsSettingsAvailable()
113.         {
114.             return ClipperSettings.instance;
115.         }
116.  
117.         public override void OnActivate(string searchContext, VisualElement rootElement)
118.         {
119.             serializedObject = ClipperSettings.GetSerializedSettings();
120.             clipDuplication = serializedObject.FindProperty("clipDuplication");
121.             autoDeletion = serializedObject.FindProperty("autoDeletion");
122.             includeFavourites = serializedObject.FindProperty("includeFavourites");
123.             daysBeforeDelete = serializedObject.FindProperty("daysBeforeDelete");
124.             clips = serializedObject.FindProperty("clips");
125.         }
126.  
127.         public override void OnGUI(string searchContext)
128.         {
129.             base.OnGUI(searchContext);
130.  
131.             EditorGUI.BeginChangeCheck();
132.             serializedObject.Update();
133.             EditorGUILayout.PropertyField(clipDuplication, new GUIContent("Clip Duplication"));
134.             EditorGUILayout.PropertyField(autoDeletion, new GUIContent("Auto Deletion"));
135.             if (autoDeletion.boolValue)
136.             {
137.                 EditorGUI.indentLevel++;
138.                 EditorGUILayout.PropertyField(includeFavourites, new GUIContent("Include Favourites"));
139.                 EditorGUILayout.PropertyField(daysBeforeDelete, new GUIContent("Days Before Delete"));
140.                 EditorGUI.indentLevel--;
141.             }
142.             Debug.Log(GUI.enabled);
143.             GUI.enabled = false;
144.             EditorGUILayout.PropertyField(clips, new GUIContent("Clips"));
145.             GUI.enabled = true;
146.             serializedObject.ApplyModifiedProperties();
147.             if (EditorGUI.EndChangeCheck())
148.             {
149.                 ClipperSettings.Save();
150.             }
151.         }
152.  
153.         public override void OnFooterBarGUI()
154.         {
155.             base.OnFooterBarGUI();
156.             EditorGUILayout.LabelField($"Version: {ClipperSettings.VERSION}");
157.         }
158.         [MenuItem("Tools/Clipper/Settings")]
159.         private static void SelectSettings()
160.         {
161.             SettingsService.OpenProjectSettings(SettingsPath);
162.         }
163.  
164.         [SettingsProvider]
165.         private static SettingsProvider CreateSettingsProvider()
166.         {
167.             // Register the SettingsProvider
168.             if (IsSettingsAvailable())
169.             {
170.                 var provider = new ClipperSettingsProvider(SettingsPath, SettingsScope.Project);
171.                 // Automatically extract all keywords from the Styles.
172.                 var keywords = GetSearchKeywordsFromGUIContentProperties<Styles>().ToList();
173.                 keywords.AddRange(new string[] { "Copy, Clip, Paste, Cut" });
174.                 provider.keywords = keywords;
175.                 return provider;
176.             }
177.  
178.             return null;
179.         }
180.     }
181. }
182.