Repository: microsoft/terminal (language: cpp)

Issue:
Disable showTabsInTitlebar -> transparent tab strip
![image](https://user-images.githubusercontent.com/18356694/169813684-61088aa5-6e35-4903-9e7a-59cd28af93b6.png)


Definitely in 1.14. Unsure if in 1.13.


Discussion / hints:

Fix patch:
diff --git a/src/cascadia/TerminalApp/TabRowControl.xaml b/src/cascadia/TerminalApp/TabRowControl.xaml
index 5f1dc2533a8..5eafe72cc6a 100644
--- a/src/cascadia/TerminalApp/TabRowControl.xaml
+++ b/src/cascadia/TerminalApp/TabRowControl.xaml
@@ -9,8 +9,11 @@
                   xmlns:local="using:TerminalApp"
                   xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
                   xmlns:mux="using:Microsoft.UI.Xaml.Controls"
+                  Background="{ThemeResource TabViewBackground}"
                   mc:Ignorable="d">
 
+    <!--  GH#13143: Make sure that the Background is actually TabViewBackground here, not Transparent. This is load bearing, for showTabsInTitlebar=false.  -->
+
     <mux:TabView x:Name="TabView"
                  VerticalAlignment="Bottom"
                  HorizontalContentAlignment="Stretch"
diff --git a/src/cascadia/TerminalApp/TerminalPage.cpp b/src/cascadia/TerminalApp/TerminalPage.cpp
index 30fcab0cc5b..e842bc8aa83 100644
--- a/src/cascadia/TerminalApp/TerminalPage.cpp
+++ b/src/cascadia/TerminalApp/TerminalPage.cpp
@@ -218,6 +218,24 @@ namespace winrt::TerminalApp::implementation
 
             // Inform the host that our titlebar content has changed.
             _SetTitleBarContentHandlers(*this, _tabRow);
+
+            // GH#13143 Manually set the tab row's background to transparent here.
+            //
+            // We're doing it this way because ThemeResources are tricky. We
+            // default in XAML to using the appropriate ThemeResource background
+            // color for our TabRow. When tabs in the titlebar are _disabled_,
+            // this will ensure that the tab row has the correct theme-dependent
+            // value. When tabs in the titlebar are _enabled_ (the default),
+            // we'll switch the BG to Transparent, to let the Titlebar Control's
+            // background be used as the BG for the tab row.
+            //
+            // We can't do it the other way around (default to Transparent, only
+            // switch to a color when disabling tabs in the titlebar), because
+            // looking up the correct ThemeResource from and App dictionary is a
+            // capital-H Hard problem.
+            const auto transparent = Media::SolidColorBrush();
+            transparent.Color(Windows::UI::Colors::Transparent());
+            _tabRow.Background(transparent);
         }
 
         // Hookup our event handlers to the ShortcutActionDispatch


Test patch: