diff --git a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetFolderRepository.cs b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetFolderRepository.cs
index 52f5f9dfd..ecad09811 100644
--- a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetFolderRepository.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetFolderRepository.cs
@@ -22,7 +22,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Assets
 {
     public sealed partial class MongoAssetFolderRepository : MongoRepositoryBase<MongoAssetFolderEntity>, IAssetFolderRepository
     {
-        private readonly Lazy<string> idField = new Lazy<string>(GetIdField);
+        private static readonly Lazy<string> IdField = new Lazy<string>(GetIdField);
 
         public MongoAssetFolderRepository(IMongoDatabase database)
             : base(database)
@@ -67,7 +67,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Assets
                     await Collection.Find(x => x.IndexedAppId == appId && !x.IsDeleted && x.ParentId == parentId).Only(x => x.Id)
                         .ToListAsync();
 
-                return assetFolderEntities.Select(x => Guid.Parse(x[idField.Value].AsString)).ToList();
+                return assetFolderEntities.Select(x => Guid.Parse(x[IdField.Value].AsString)).ToList();
             }
         }
 
diff --git a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetRepository.cs b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetRepository.cs
index 0815d928b..543b0b429 100644
--- a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetRepository.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetRepository.cs
@@ -25,7 +25,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Assets
 {
     public sealed partial class MongoAssetRepository : MongoRepositoryBase<MongoAssetEntity>, IAssetRepository
     {
-        private readonly Lazy<string> idField = new Lazy<string>(GetIdField);
+        private static readonly Lazy<string> IdField = new Lazy<string>(GetIdField);
 
         public MongoAssetRepository(IMongoDatabase database)
             : base(database)
@@ -103,7 +103,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Assets
                     await Collection.Find(BuildFilter(appId, ids)).Only(x => x.Id)
                         .ToListAsync();
 
-                return assetEntities.Select(x => Guid.Parse(x[idField.Value].AsString)).ToList();
+                return assetEntities.Select(x => Guid.Parse(x[IdField.Value].AsString)).ToList();
             }
         }
 
@@ -115,7 +115,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Assets
                     await Collection.Find(x => x.IndexedAppId == appId && !x.IsDeleted && x.ParentId == parentId).Only(x => x.Id)
                         .ToListAsync();
 
-                return assetEntities.Select(x => Guid.Parse(x[idField.Value].AsString)).ToList();
+                return assetEntities.Select(x => Guid.Parse(x[IdField.Value].AsString)).ToList();
             }
         }
 
diff --git a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/Operations/QueryIdsAsync.cs b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/Operations/QueryIdsAsync.cs
index b751525ea..dd0c32eae 100644
--- a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/Operations/QueryIdsAsync.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Contents/Operations/QueryIdsAsync.cs
@@ -20,9 +20,9 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents.Operations
 {
     internal sealed class QueryIdsAsync : OperationBase
     {
-        private readonly Lazy<string> idField = new Lazy<string>(GetIdField);
-        private readonly Lazy<string> schemaIdField = new Lazy<string>(GetSchemaIdField);
         private static readonly List<(Guid SchemaId, Guid Id)> EmptyIds = new List<(Guid SchemaId, Guid Id)>();
+        private static readonly Lazy<string> IdField = new Lazy<string>(GetIdField);
+        private static readonly Lazy<string> SchemaIdField = new Lazy<string>(GetSchemaIdField);
         private readonly IAppProvider appProvider;
 
         public QueryIdsAsync(IAppProvider appProvider)
@@ -52,7 +52,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents.Operations
                 await Collection.Find(filter).Only(x => x.Id, x => x.IndexedSchemaId)
                     .ToListAsync();
 
-            return contentEntities.Select(x => (Guid.Parse(x[schemaIdField.Value].AsString), Guid.Parse(x[idField.Value].AsString))).ToList();
+            return contentEntities.Select(x => (Guid.Parse(x[SchemaIdField.Value].AsString), Guid.Parse(x[IdField.Value].AsString))).ToList();
         }
 
         public async Task<IReadOnlyList<(Guid SchemaId, Guid Id)>> DoAsync(Guid appId, Guid schemaId, FilterNode<ClrValue> filterNode)
@@ -70,7 +70,7 @@ namespace Squidex.Domain.Apps.Entities.MongoDb.Contents.Operations
                 await Collection.Find(filter).Only(x => x.Id, x => x.IndexedSchemaId)
                     .ToListAsync();
 
-            return contentEntities.Select(x => (Guid.Parse(x[schemaIdField.Value].AsString), Guid.Parse(x[idField.Value].AsString))).ToList();
+            return contentEntities.Select(x => (Guid.Parse(x[SchemaIdField.Value].AsString), Guid.Parse(x[IdField.Value].AsString))).ToList();
         }
 
         public static FilterDefinition<MongoContentEntity> BuildFilter(FilterNode<ClrValue>? filterNode, Guid schemaId)