diff --git a/src/Calculator/App.xaml b/src/Calculator/App.xaml
index a08fb6d..f27dcdf 100644
--- a/src/Calculator/App.xaml
+++ b/src/Calculator/App.xaml
@@ -28,8 +28,8 @@
                                      Opacity="0.4"
                                      Color="{ThemeResource SystemAltMediumLowColor}"/>
                     <SolidColorBrush x:Key="AppControlPageTextBaseMediumHighBrush" Color="{StaticResource SystemBaseMediumHighColor}"/>
-                    <RevealBackgroundBrush x:Key="AppControlHoverButtonFaceBrush" Color="#18FFFFFF"/>
-                    <RevealBackgroundBrush x:Key="AppControlPressedButtonFaceBrush" Color="#30FFFFFF"/>
+                    <RevealBackgroundBrush x:Key="AppControlHoverButtonFaceBrush" Color="#18FFFFFF" FallbackColor="#18FFFFFF"/>
+                    <RevealBackgroundBrush x:Key="AppControlPressedButtonFaceBrush" Color="#30FFFFFF" FallbackColor="#30FFFFFF"/>
                     <SolidColorBrush x:Key="AppControlTransparentAccentColorBrush" Color="{ThemeResource SystemAccentColor}"/>
                     <SolidColorBrush x:Key="AppControlPageTextBaseHighColorBrush" Color="{StaticResource SystemBaseHighColor}"/>
                     <SolidColorBrush x:Key="OperatorPanelScrollButtonBackgroundBrush" Color="{ThemeResource OperatorPanelScrollButtonBackgroundColor}"/>
@@ -80,8 +80,8 @@
                                      Opacity="0.4"
                                      Color="{ThemeResource SystemAltMediumLowColor}"/>
                     <SolidColorBrush x:Key="AppControlPageTextBaseMediumHighBrush" Color="{StaticResource SystemBaseMediumHighColor}"/>
-                    <RevealBackgroundBrush x:Key="AppControlHoverButtonFaceBrush" Color="#17000000"/>
-                    <RevealBackgroundBrush x:Key="AppControlPressedButtonFaceBrush" Color="#30000000"/>
+                    <RevealBackgroundBrush x:Key="AppControlHoverButtonFaceBrush" Color="#17000000" FallbackColor="#17000000"/>
+                    <RevealBackgroundBrush x:Key="AppControlPressedButtonFaceBrush" Color="#30000000" FallbackColor="#30000000"/>
                     <SolidColorBrush x:Key="AppControlTransparentAccentColorBrush" Color="{ThemeResource SystemAccentColor}"/>
                     <SolidColorBrush x:Key="AppControlPageTextBaseHighColorBrush" Color="{StaticResource SystemBaseHighColor}"/>
                     <SolidColorBrush x:Key="OperatorPanelScrollButtonBackgroundBrush" Color="{ThemeResource OperatorPanelScrollButtonBackgroundColor}"/>