diff --git a/zero.Core/Services/Localizer.cs b/zero.Core/Services/Localizer.cs
index 3dd772c6..2efa5023 100644
--- a/zero.Core/Services/Localizer.cs
+++ b/zero.Core/Services/Localizer.cs
@@ -50,7 +50,7 @@ namespace zero.Core.Services
 
         value = translation.Value;
 
-        lock (Cache)
+        lock (Cache) // TOOD use concurrent dictionary
         {
           Cache[key] = value;
         }