diff --git a/csharp/App/Backend/Controllers/Controller.cs b/csharp/App/Backend/Controllers/Controller.cs
index f4dd895d3..269a5e736 100644
--- a/csharp/App/Backend/Controllers/Controller.cs
+++ b/csharp/App/Backend/Controllers/Controller.cs
@@ -76,7 +76,7 @@ public class Controller : ControllerBase
         if (installation is null || !user.HasAccessTo(installation))
             return Unauthorized();
     
-        return installation.HideParentIfUserHasNoAccessToParent(user);
+        return installation.FillOrderNumbers().HideParentIfUserHasNoAccessToParent(user);
     }
     
     [HttpGet(nameof(GetUsersWithDirectAccessToInstallation))]
@@ -253,7 +253,7 @@ public class Controller : ControllerBase
         if (! await session.Create(installation))
             return Unauthorized();
         
-        return installation.HideParentIfUserHasNoAccessToParent(session!.User);
+        return installation.FillOrderNumbers().HideParentIfUserHasNoAccessToParent(session!.User);
     }
     
     [HttpPost(nameof(CreateFolder))]
@@ -359,7 +359,7 @@ public class Controller : ControllerBase
         if (!session.Update(installation))
             return Unauthorized();
         
-        return installation.HideParentIfUserHasNoAccessToParent(session.User);
+        return installation.FillOrderNumbers().HideParentIfUserHasNoAccessToParent(session!.User);
     }
     
     
@@ -371,7 +371,7 @@ public class Controller : ControllerBase
         if (!session.Update(folder))
             return Unauthorized();
         
-        return folder.HideParentIfUserHasNoAccessToParent(session.User);
+        return folder.HideParentIfUserHasNoAccessToParent(session!.User);
     }
     
     [HttpPut(nameof(MoveInstallation))]