diff --git a/src/NuGet.Clients/NuGet.PackageManagement.UI/Options/AddMappingDialog.xaml b/src/NuGet.Clients/NuGet.PackageManagement.UI/Options/AddMappingDialog.xaml
index ef7302968f8..60a82d07e86 100644
--- a/src/NuGet.Clients/NuGet.PackageManagement.UI/Options/AddMappingDialog.xaml
+++ b/src/NuGet.Clients/NuGet.PackageManagement.UI/Options/AddMappingDialog.xaml
@@ -27,6 +27,47 @@
       <Style TargetType="ScrollBar">
         <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ScrollBarColorKey}}"/>
       </Style>
+      <!-- Copied from ThemedDialogResources.xaml. See https://github.com/NuGet/Home/issues/12163 -->
+      <Style TargetType="{x:Type vsui:WatermarkedTextBox}">
+        <Setter Property="Padding" Value="6,8,6,8" />
+        <Setter Property="AutomationProperties.HelpText" Value="{Binding Watermark}" />
+        <Setter Property="Template">
+          <Setter.Value>
+            <ControlTemplate TargetType="{x:Type vsui:WatermarkedTextBox}">
+              <Border x:Name="border"
+                      BorderBrush="{TemplateBinding BorderBrush}"
+                      BorderThickness="{TemplateBinding BorderThickness}"
+                      Background="{TemplateBinding Background}"
+                      SnapsToDevicePixels="True">
+                <Grid>
+                  <ScrollViewer x:Name="PART_ContentHost"
+                                Padding="{TemplateBinding Padding}"
+                                Focusable="false"
+                                HorizontalScrollBarVisibility="Hidden"
+                                VerticalScrollBarVisibility="Hidden"/>
+                  <TextBlock VerticalAlignment="Center"
+                             x:Name="WatermarkTextBlock"
+                             Visibility="Collapsed"
+                             Cursor="IBeam"
+                             Padding="{TemplateBinding Padding}"
+                             Margin="2,0,0,0"
+                             Text="{TemplateBinding Watermark}"
+                             IsHitTestVisible="False"
+                             Foreground="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
+                </Grid>
+              </Border>
+              <ControlTemplate.Triggers>
+                <Trigger Property="IsEnabled" Value="false">
+                  <Setter Property="Opacity" TargetName="border" Value="0.56"/>
+                </Trigger>
+                <Trigger Property="Text" Value="">
+                  <Setter TargetName="WatermarkTextBlock" Property="Visibility" Value="Visible" />
+                </Trigger>
+              </ControlTemplate.Triggers>
+            </ControlTemplate>
+          </Setter.Value>
+        </Setter>
+      </Style>
     </Grid.Resources>
     <StackPanel Grid.Row="0">
       <Grid>
@@ -63,18 +104,18 @@
     <StackPanel Grid.Row="1">
       <Grid>
         <Grid.RowDefinitions>
-          <RowDefinition Height="48"/>
-          <RowDefinition Height="*"/>
-          <RowDefinition Height="36"/>
+          <RowDefinition Height="Auto"/>
+          <RowDefinition Height="Auto"/>
+          <RowDefinition Height="Auto"/>
         </Grid.RowDefinitions>
         <vsui:WatermarkedTextBox Grid.Row="0"
+                                 BorderBrush="{DynamicResource {x:Static vsui:CommonControlsColors.ButtonBorderBrushKey}}"
+                                 BorderThickness="1"
                                  AutomationProperties.Name="{x:Static nuget:Resources.VSOptions_Watermark_AddPackageNamespace}"
                                  x:Name="_packageID"
                                  MaxLength="100"
                                  Margin="12,6,12,6"
                                  Watermark="{x:Static nuget:Resources.VSOptions_Watermark_AddPackageNamespace}"
-                                 Foreground="{Binding Path=(TextElement.Foreground), RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"
-                                 Background="{Binding Path=(Window.Background), RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"
                                  TextChanged="PackageID_TextChanged"/>
         <StackPanel Orientation="Vertical"  Grid.Row="1">
           <nuget:ProjectsListView AutomationProperties.Name="{x:Static nuget:Resources.VSOptions_Accessibility_SourcesList}"