diff --git a/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs b/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs
index 43b39fe..ec97152 100644
--- a/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs
+++ b/Pilz.UI.Telerik/Extensions/RadFlyoutBaseExtensions.cs
@@ -5,7 +5,7 @@ namespace Pilz.UI.Telerik.Extensions.Extensions;
 
 public static class RadFlyoutBaseExtensions
 {
-    public static bool IsValid([NotNullWhen(true)] this RadFlyoutBase @this)
+    public static bool IsValid([NotNullWhen(true)] this RadFlyoutBase? @this)
     {
         return @this != null && @this.Result == DialogResult.OK;
     }
diff --git a/Pilz.UI/Extensions/FlyoutBaseExtensions.cs b/Pilz.UI/Extensions/FlyoutBaseExtensions.cs
index 05eb2fa..914038e 100644
--- a/Pilz.UI/Extensions/FlyoutBaseExtensions.cs
+++ b/Pilz.UI/Extensions/FlyoutBaseExtensions.cs
@@ -5,7 +5,7 @@ namespace Pilz.UI.Extensions;
 
 public static class FlyoutBaseExtensions
 {
-    public static bool IsValid([NotNullWhen(true)] this FlyoutBase @this)
+    public static bool IsValid([NotNullWhen(true)] this FlyoutBase? @this)
     {
         return @this != null && @this.Result == DialogResult.OK;
     }