Merge pull request 61424 from bugfix/statics-and-singletons-leaks into tag/v1.2.4

Author: emitrackman

Runtime/Extensions/NodeExtensions.cs

@@ -39,6 +39,16 @@ record Metadata(UIDocument document, UxmlAttribute uxml, string path);
         public static Action<VisualElement> OnRebuildElement { get; set; }
         #endregion
 
+        #region Constructors
+        static VisualElementMetadata() => DisposeStatic.OnDisposeStatic += () =>
+        {
+            rootMetadata.Clear();
+            search.Clear();
+            cloneMap.Clear();
+            hide.Clear();
+        };
+        #endregion
+
         #region Methods
         public static void Initialize(UIDocument document, IEnumerable<IRootElement> targets)
         {

Runtime/Extensions/VisualElementExtensions.cs

@@ -12,6 +12,10 @@ public static class VisualElementExtensions
         static Dictionary<(VisualElement prefab, VisualElement parent), IList> cloneDictionary = new();
         #endregion
 
+        #region Constructors
+        static VisualElementExtensions() => DisposeStatic.OnDisposeStatic += () => cloneDictionary.Clear();
+        #endregion
+
         #region Methods
         public static bool HasVisibility(this VisualElement element) => element.style.visibility == Visibility.Visible;
         public static void MakeVisible(this VisualElement element) => element.style.visibility = Visibility.Visible;