[PTRun]Fix WPF transparent border issue on Windows 10 (#36392)

* Added border on W10

* Added a comment

---------
Co-authored-by: Davide Giacometti <25966642+davidegiacometti@users.noreply.github.com>

src/modules/launcher/PowerLauncher/MainWindow.xaml

@@ -27,6 +27,7 @@
     WindowStartupLocation="Manual"
     WindowStyle="None"
     mc:Ignorable="d">
+    <Border x:Name="MainBorder" BorderBrush="{DynamicResource {x:Static SystemColors.ActiveBorderBrushKey}}">
         <Grid x:Name="RootGrid" MouseDown="OnMouseDown">
             <Grid.RowDefinitions>
                 <RowDefinition Height="Auto" />
@@ -130,6 +131,7 @@
                 Visibility="{Binding Results.Visibility}" />
 
         </Grid>
+    </Border>
     <Window.InputBindings>
         <KeyBinding Key="Escape" Command="{Binding EscCommand}" />
         <KeyBinding Key="Enter" Command="{Binding OpenResultWithKeyboardCommand}" />

src/modules/launcher/PowerLauncher/MainWindow.xaml.cs

@@ -200,6 +200,11 @@ namespace PowerLauncher
                 DWM_WINDOW_CORNER_PREFERENCE preference = DWM_WINDOW_CORNER_PREFERENCE.DWMWCP_ROUND;
                 DwmSetWindowAttribute(hWnd, attribute, ref preference, sizeof(uint));
             }
+            else
+            {
+                // On Windows10 ResizeMode="NoResize" removes the border so we add a new one.
+                MainBorder.BorderThickness = new System.Windows.Thickness(0.5);
+            }
         }
 
         private void OnLoaded(object sender, RoutedEventArgs e)