diff --git a/src/cascadia/TerminalApp/App.xaml b/src/cascadia/TerminalApp/App.xaml
index 22cd0f9849..bfdd08b1ab 100644
--- a/src/cascadia/TerminalApp/App.xaml
+++ b/src/cascadia/TerminalApp/App.xaml
@@ -63,25 +63,23 @@
 
 
 
-                            <SolidColorBrush x:Key="UnfocusedBorderBrush"
-                                             Color="{ThemeResource ApplicationPageBackgroundThemeBrush}" />
+                            <StaticResource x:Key="UnfocusedBorderBrush"
+                                            ResourceKey="ApplicationPageBackgroundThemeBrush" />
 
 
                         </ResourceDictionary>
 
                         <ResourceDictionary x:Key="Light">
                             <!--  Define resources for Light mode here  -->
-                            <!-- <SolidColorBrush x:Key="TabViewBackground"
-                                            Color="{ThemeResource SolidBackgroundFillColorBase}" />-->
-                            <!-- <SolidColorBrush x:Key="TabViewBackground"
-                                            Color="{StaticResource SolidBackgroundFillColorBase}" />-->
+
+                            <!--  This is the color of ApplicationPageBackgroundThemeBrush, which is evaluated as SolidBackgroundFillColorBase. If we try to use those resources directly though, we don't get the properly themed versions. Presumably because the App itself can't have it's RequestedTheme changed at runtime.  -->
                             <SolidColorBrush x:Key="TabViewBackground"
                                              Color="#F3F3F3" />
 
 
 
-                            <SolidColorBrush x:Key="UnfocusedBorderBrush"
-                                             Color="{ThemeResource ApplicationPageBackgroundThemeBrush}" />
+                            <StaticResource x:Key="UnfocusedBorderBrush"
+                                            ResourceKey="ApplicationPageBackgroundThemeBrush" />
 
 
                         </ResourceDictionary>