diff --git a/src/OneScript.StandardLibrary/Xml/XmlGlobalFunctions.cs b/src/OneScript.StandardLibrary/Xml/XmlGlobalFunctions.cs
index fe5d82420..1a6ea7214 100644
--- a/src/OneScript.StandardLibrary/Xml/XmlGlobalFunctions.cs
+++ b/src/OneScript.StandardLibrary/Xml/XmlGlobalFunctions.cs
@@ -29,6 +29,9 @@ private static readonly Dictionary<Type, EnumerationContext> _allowedEnums
         
         private XmlGlobalFunctions(IGlobalsManager mgr)
         {
+            if (_allowedEnums.Count > 0)
+                return;
+
             foreach (var e in new[] {
                          (typeof(ClrEnumValueWrapper<AllowedSignEnum>), typeof(AllowedSignEnum)),
                          (typeof(ClrEnumValueWrapper<AllowedLengthEnum>), typeof(AllowedLengthEnum)),