diff --git a/samples/BindingDemo/MainWindow.xaml b/samples/BindingDemo/MainWindow.xaml
index a232a06383..b57a9a0a9e 100644
--- a/samples/BindingDemo/MainWindow.xaml
+++ b/samples/BindingDemo/MainWindow.xaml
@@ -24,6 +24,9 @@
+
diff --git a/src/Avalonia.Base/Data/Core/ExpressionNode.cs b/src/Avalonia.Base/Data/Core/ExpressionNode.cs
index ce40b3e517..c2e5c8e4f3 100644
--- a/src/Avalonia.Base/Data/Core/ExpressionNode.cs
+++ b/src/Avalonia.Base/Data/Core/ExpressionNode.cs
@@ -8,9 +8,13 @@ namespace Avalonia.Data.Core
public abstract class ExpressionNode
{
private static readonly object CacheInvalid = new object();
+
protected static readonly WeakReference