diff --git a/Tools/IObservableHashCollection.cs b/Tools/IObservableHashCollection.cs
index 6cfc32d..4da7f67 100644
--- a/Tools/IObservableHashCollection.cs
+++ b/Tools/IObservableHashCollection.cs
@@ -3,6 +3,7 @@
     using System.Collections.Generic;
     using System.Collections.Specialized;
     using System.ComponentModel;
+    using Core.Tools;
 
     public interface IObservableHashCollection : INotifyCollectionChanged, INotifyPropertyChanged
     {
diff --git a/Tools/ObservableHashCollection.cs b/Tools/ObservableHashCollection.cs
index 6428df9..e43f016 100644
--- a/Tools/ObservableHashCollection.cs
+++ b/Tools/ObservableHashCollection.cs
@@ -3,6 +3,8 @@
     using System.Collections.Generic;
     using System.Collections.Specialized;
     using System.ComponentModel;
+    using System.Linq;
+    using Core.Tools;
 
     public class ObservableHashCollection<TItem> : HashCollection<TItem>, IObservableHashCollection
         where TItem : IStringIdItem
diff --git a/Tools/SettingsContainer.cs b/Tools/SettingsContainer.cs
index 2060a53..528a690 100644
--- a/Tools/SettingsContainer.cs
+++ b/Tools/SettingsContainer.cs
@@ -6,6 +6,7 @@ namespace GMaster.Tools
     using System.ComponentModel;
     using System.Reflection;
     using System.Runtime.CompilerServices;
+    using Core.Tools;
     using Newtonsoft.Json.Linq;
 
     public class SettingsContainer : INotifyPropertyChanged