Stop updating AutoSuggestBox on selection redux (#18010)

I wrote a big comment next to the changes I made.
This is a redo of #17961 which had various issues.

Closes #17916
Closes #18070 

## Validation Steps Performed
* Pressing Enter within the input line doesn't crash ✅
* Type "Cour" and pick Courier New, press Save = Saved ✅
* Pick any other font from the dropdown, press Save = Saved ✅
* Picking an option dismisses focus but not to the tab row ✅
* The first time after launching the SUI, when the setting is still
  unmodified, when you focus the box and pick an option,
  it'll unfocus the box ✅
* When the setting is unmodified, and you pick the default
  (Cascadia Mono), it'll still unfocus the box ✅

.github/actions/spelling/expect/expect.txt

@@ -1464,6 +1464,7 @@ QWER
 Qxxxxxxxxxxxxxxx
 qzmp
 RAII
+Ralph
 RALT
 rasterbar
 rasterfont
@@ -2013,6 +2014,7 @@ WHelper
 wic
 WIDTHSCROLL
 Widthx
+Wiggum
 wil
 WImpl
 WINAPI

src/cascadia/TerminalSettingsEditor/Appearances.cpp

@@ -1052,22 +1052,18 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 
     void Appearances::FontFaceBox_LostFocus(const IInspectable& sender, const RoutedEventArgs&)
     {
-        const auto appearance = Appearance();
-        const auto fontSpec = sender.as<AutoSuggestBox>().Text();
+        _updateFontName(sender.as<AutoSuggestBox>().Text());
+    }
 
-        if (fontSpec.empty())
-        {
-            appearance.ClearFontFace();
-        }
-        else
+    void Appearances::FontFaceBox_QuerySubmitted(const AutoSuggestBox& sender, const AutoSuggestBoxQuerySubmittedEventArgs& args)
+    {
+        // When pressing Enter within the input line, this callback will be invoked with no suggestion.
+        const auto font = unbox_value_or<Editor::Font>(args.ChosenSuggestion(), nullptr);
+        if (!font)
         {
-            appearance.FontFace(fontSpec);
+            return;
         }
-    }
 
-    void Appearances::FontFaceBox_SuggestionChosen(const AutoSuggestBox& sender, const AutoSuggestBoxSuggestionChosenEventArgs& args)
-    {
-        const auto font = unbox_value<Editor::Font>(args.SelectedItem());
         const auto fontName = font.Name();
         auto fontSpec = sender.Text();
 
@@ -1084,6 +1080,22 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         }
 
         sender.Text(fontSpec);
+
+        // Normally we'd just update the model property in LostFocus above, but because WinUI is the Ralph Wiggum
+        // among the UI frameworks, it raises the LostFocus event _before_ the QuerySubmitted event.
+        // So, when you press Save, the model will have the wrong font face string, because LostFocus was raised too early.
+        // Also, this causes the first tab in the application to be focused, so when you press Enter it'll switch tabs.
+        //
+        // You can't just assign focus back to the AutoSuggestBox, because the FocusState() within the GotFocus event handler
+        // contains random values. This prevents us from avoiding the IsSuggestionListOpen(true) in our GotFocus event handler.
+        // You can't just do IsSuggestionListOpen(false) either, because you can show the list with that property but not hide it.
+        // So, we update the model manually and assign focus to the parent container.
+        //
+        // BUT you can't just focus the parent container, because of a weird interaction with AutoSuggestBox where it'll refuse to lose
+        // focus if you picked a suggestion that matches the current fontSpec. So, we unfocus it first and then focus the parent container.
+        _updateFontName(fontSpec);
+        sender.Focus(FocusState::Unfocused);
+        FontFaceContainer().Focus(FocusState::Programmatic);
     }
 
     void Appearances::FontFaceBox_TextChanged(const AutoSuggestBox& sender, const AutoSuggestBoxTextChangedEventArgs& args)
@@ -1106,6 +1118,19 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         _updateFontNameFilter(filter);
     }
 
+    void Appearances::_updateFontName(hstring fontSpec)
+    {
+        const auto appearance = Appearance();
+        if (fontSpec.empty())
+        {
+            appearance.ClearFontFace();
+        }
+        else
+        {
+            appearance.FontFace(std::move(fontSpec));
+        }
+    }
+
     void Appearances::_updateFontNameFilter(std::wstring_view filter)
     {
         if (_fontNameFilter != filter)

src/cascadia/TerminalSettingsEditor/Appearances.h

@@ -187,7 +187,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 
         void FontFaceBox_GotFocus(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
         void FontFaceBox_LostFocus(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
-        void FontFaceBox_SuggestionChosen(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxSuggestionChosenEventArgs&);
+        void FontFaceBox_QuerySubmitted(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxQuerySubmittedEventArgs&);
         void FontFaceBox_TextChanged(const winrt::Windows::UI::Xaml::Controls::AutoSuggestBox&, const winrt::Windows::UI::Xaml::Controls::AutoSuggestBoxTextChangedEventArgs&);
         void DeleteFontKeyValuePair_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
         safe_void_coroutine BackgroundImage_Click(const Windows::Foundation::IInspectable& sender, const Windows::UI::Xaml::RoutedEventArgs& e);
@@ -222,9 +222,11 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
         Windows::Foundation::Collections::IObservableVector<winrt::hstring> _FontFeaturesNames;
         std::wstring _fontNameFilter;
         bool _ShowAllFonts = false;
+        bool _suppressFontFaceBoxList = false;
 
         static void _ViewModelChanged(const Windows::UI::Xaml::DependencyObject& d, const Windows::UI::Xaml::DependencyPropertyChangedEventArgs& e);
 
+        void _updateFontName(winrt::hstring fontSpec);
         void _updateFontNameFilter(std::wstring_view filter);
         void _updateFilteredFontList();
         void _UpdateBIAlignmentControl(const int32_t val);

src/cascadia/TerminalSettingsEditor/Appearances.xaml

@@ -202,7 +202,8 @@
             </local:SettingContainer>
 
             <!--  Font Face  -->
-            <local:SettingContainer x:Uid="Profile_FontFace"
+            <local:SettingContainer x:Name="FontFaceContainer"
+                                    x:Uid="Profile_FontFace"
                                     ClearSettingValue="{x:Bind Appearance.ClearFontFace}"
                                     HasSettingValue="{x:Bind Appearance.HasFontFace, Mode=OneWay}"
                                     SettingOverrideSource="{x:Bind Appearance.FontFaceOverrideSource, Mode=OneWay}"
@@ -214,10 +215,11 @@
                                     ItemTemplate="{StaticResource FontFaceComboBoxItemTemplate}"
                                     ItemsSource="{x:Bind FilteredFontList, Mode=OneWay}"
                                     LostFocus="FontFaceBox_LostFocus"
-                                    SuggestionChosen="FontFaceBox_SuggestionChosen"
+                                    QuerySubmitted="FontFaceBox_QuerySubmitted"
                                     Text="{x:Bind Appearance.FontFace, Mode=OneWay}"
                                     TextBoxStyle="{StaticResource TextBoxSettingStyle}"
-                                    TextChanged="FontFaceBox_TextChanged" />
+                                    TextChanged="FontFaceBox_TextChanged"
+                                    UpdateTextOnSelect="False" />
                     <CheckBox x:Name="ShowAllFontsCheckbox"
                               x:Uid="Profile_FontFaceShowAllFonts"
                               IsChecked="{x:Bind ShowAllFonts, Mode=TwoWay}" />