diff --git a/WinUIGallery/Samples/SystemBackdropElement/SystemBackdropElementPage.xaml b/WinUIGallery/Samples/SystemBackdropElement/SystemBackdropElementPage.xaml
index 682e359c0..2a9171e96 100644
--- a/WinUIGallery/Samples/SystemBackdropElement/SystemBackdropElementPage.xaml
+++ b/WinUIGallery/Samples/SystemBackdropElement/SystemBackdropElementPage.xaml
@@ -53,5 +53,9 @@
                 <controls:ControlExampleSubstitution Key="CornerRadius" Value="{x:Bind CornerRadiusSlider.Value, Mode=OneWay}" />
             </controls:ControlExample.Substitutions>
         </controls:ControlExample>
+        <TextBlock
+            Margin="0,12,0,0"
+            Text="Theme updates for SystemBackdropElement are triggered by app or OS theme changes, not by setting theme directly on the control."
+            TextWrapping="WrapWholeWords" />
     </StackPanel>
 </Page>