diff --git a/src/Avalonia.Controls/ContextMenu.cs b/src/Avalonia.Controls/ContextMenu.cs
index 38da6f6e72..a6242721b4 100644
--- a/src/Avalonia.Controls/ContextMenu.cs
+++ b/src/Avalonia.Controls/ContextMenu.cs
@@ -58,7 +58,7 @@ namespace Avalonia.Controls
         /// Defines the <see cref="PlacementMode"/> property.
         /// </summary>
         [Obsolete("Use the Placement property instead.")]
-        public static readonly StyledProperty<PlacementMode> PlacementModeProperty = PlacementProperty;
+        public static readonly StyledProperty<PlacementMode> PlacementModeProperty = PlacementProperty!;
 
 #pragma warning disable AVP1013 // AvaloniaProperty owners should not be added superfluously
 
diff --git a/src/Avalonia.Controls/Primitives/Popup.cs b/src/Avalonia.Controls/Primitives/Popup.cs
index e4fadcdf67..da21cc6439 100644
--- a/src/Avalonia.Controls/Primitives/Popup.cs
+++ b/src/Avalonia.Controls/Primitives/Popup.cs
@@ -69,7 +69,7 @@ namespace Avalonia.Controls.Primitives
         /// Defines the <see cref="PlacementMode"/> property.
         /// </summary>
         [Obsolete("Use the Placement property instead.")]
-        public static readonly StyledProperty<PlacementMode> PlacementModeProperty = PlacementProperty;
+        public static readonly StyledProperty<PlacementMode> PlacementModeProperty = PlacementProperty!;
 
         /// <summary>
         /// Defines the <see cref="Placement"/> property.