From 200d2ddfd55b62642e4eac4ea7b5f5d1c2ddbabf Mon Sep 17 00:00:00 2001
From: Hugh Bellamy <hughbellars@gmail.com>
Date: Mon, 13 Jan 2020 09:01:53 +0000
Subject: [PATCH] Fix BindingContext.SyncRoot

---
 .../src/System/Windows/Forms/BindingContext.cs                  | 2 +-
 .../tests/UnitTests/System/Windows/Forms/BindingContextTests.cs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/BindingContext.cs b/src/System.Windows.Forms/src/System/Windows/Forms/BindingContext.cs
index cad0a5ae941..d489f7ccc44 100644
--- a/src/System.Windows.Forms/src/System/Windows/Forms/BindingContext.cs
+++ b/src/System.Windows.Forms/src/System/Windows/Forms/BindingContext.cs
@@ -70,7 +70,7 @@ IEnumerator IEnumerable.GetEnumerator()
         /// <summary>
         ///  Gets an object to use for synchronization (thread safety).
         /// </summary>
-        object ICollection.SyncRoot => null;
+        object ICollection.SyncRoot => this;
 
         /// <summary>
         ///  Gets the System.Windows.Forms.BindingManagerBase associated with the specified
diff --git a/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/BindingContextTests.cs b/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/BindingContextTests.cs
index bebdda99ee2..defecb598d2 100644
--- a/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/BindingContextTests.cs
+++ b/src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/BindingContextTests.cs
@@ -26,7 +26,7 @@ public void BindingContext_ICollection_GetProperties_ReturnsExpected()
         {
             ICollection context = new BindingContext();
             Assert.False(context.IsSynchronized);
-            Assert.Null(context.SyncRoot);
+            Assert.Same(context, context.SyncRoot);
             Assert.Empty(context);
         }