Fix crash due to alive reference to old asset validator

#3081

Source/Editor/Content/AssetPickerValidator.cs

@@ -1,7 +1,6 @@
 // Copyright (c) 2012-2024 Wojciech Figat. All rights reserved.
 
 using System;
-using System.IO;
 using FlaxEditor.Scripting;
 using FlaxEngine;
 using FlaxEngine.Utilities;

Source/Editor/CustomEditors/Editors/AssetRefEditor.cs

@@ -292,5 +292,17 @@ namespace FlaxEditor.CustomEditors.Editors
                 _isRefreshing = false;
             }
         }
+
+        /// <inheritdoc />
+        protected override void Deinitialize()
+        {
+            if (_validator != null)
+            {
+                _validator.OnDestroy();
+                _validator = null;
+            }
+
+            base.Deinitialize();
+        }
     }
 }

Source/Editor/CustomEditors/Editors/CollectionEditor.cs

@@ -898,9 +898,13 @@ namespace FlaxEditor.CustomEditors.Editors
                 base.Draw();
             }
 
+            /// <inheritdoc />
             public override void OnDestroy()
             {
                 _pickerValidator.OnDestroy();
+                _pickerValidator = null;
+
+                base.OnDestroy();
             }
 
             private bool ValidateActors(ActorNode node)

Source/Editor/GUI/AssetPicker.cs

@@ -59,7 +59,7 @@ namespace FlaxEditor.GUI
         /// <summary>
         /// Initializes a new instance of the <see cref="AssetPicker"/> class.
         /// </summary>
-        /// <param name="assetType">The assets types that this picker accepts.</param>
+        /// <param name="assetType">The asset types that this picker accepts.</param>
         /// <param name="location">The control location.</param>
         public AssetPicker(ScriptType assetType, Float2 location)
         : base(location, new Float2(DefaultIconSize + ButtonsOffset + ButtonsSize, DefaultIconSize))