Add per-pane title header for split panes (#4717)

src/cascadia/TerminalApp/Pane.cpp

@@ -31,10 +31,14 @@ Pane::Pane(IPaneContent content, const bool lastFocused) :
     _lastActive{ lastFocused }
 {
     _setPaneContent(std::move(content));
-    _root.Children().Append(_borderFirst);
+    _CreatePaneHeader();
 
     const auto& control{ _content.GetRoot() };
-    _borderFirst.Child(control);
+
+    // Set up leaf layout: header in _root row 0, content in _borderFirst row 1.
+    // The TermControl stays as the direct child of _borderFirst (no Grid wrapper)
+    // so the SwapChainPanel renders correctly.
+    _SetupLeafLayout(control);
 
     // Register an event with the control to have it inform us when it gains focus.
     if (control)
@@ -1228,6 +1232,12 @@ void Pane::UpdateVisuals()
     const auto& brush{ _ComputeBorderColor() };
     _borderFirst.BorderBrush(brush);
     _borderSecond.BorderBrush(brush);
+
+    // Update pane header color to match focus state
+    if (_paneHeaderBorder && _paneHeaderBorder.Visibility() == winrt::Windows::UI::Xaml::Visibility::Visible)
+    {
+        _paneHeaderBorder.Background(brush);
+    }
 }
 
 // Method Description:
@@ -1450,9 +1460,9 @@ void Pane::_CloseChild(const bool closeFirst)
         _root.RowDefinitions().Clear();
 
         // Reattach the TermControl to our grid.
-        _root.Children().Append(_borderFirst);
+        _CreatePaneHeader();
         const auto& control{ _content.GetRoot() };
-        _borderFirst.Child(control);
+        _SetupLeafLayout(control);
 
         // Make sure to set our _splitState before focusing the control. If you
         // fail to do this, when the tab handles the GotFocus event and asks us
@@ -1755,7 +1765,92 @@ void Pane::_setPaneContent(IPaneContent content)
 }
 
 // Method Description:
-// - Sets up row/column definitions for this pane. There are three total
+// - Creates the pane header UI elements (title bar shown above the content).
+//   The header is initially collapsed and only shown via ShowPaneHeaders().
+void Pane::_CreatePaneHeader()
+{
+    namespace WUX = winrt::Windows::UI::Xaml;
+
+    _paneHeaderText = Controls::TextBlock{};
+    _paneHeaderText.FontSize(12);
+    _paneHeaderText.Padding({ 8, 2, 8, 2 });
+    _paneHeaderText.IsTextSelectionEnabled(false);
+    _paneHeaderText.TextTrimming(WUX::TextTrimming::CharacterEllipsis);
+    if (_content)
+    {
+        _paneHeaderText.Text(_content.Title());
+        _titleChangedRevoker = _content.TitleChanged(winrt::auto_revoke, [this](auto&&, auto&&) {
+            _paneHeaderBorder.Dispatcher().RunAsync(
+                winrt::Windows::UI::Core::CoreDispatcherPriority::Normal,
+                [this]() {
+                    if (_content && _paneHeaderText)
+                    {
+                        _paneHeaderText.Text(_content.Title());
+                    }
+                });
+        });
+    }
+
+    _paneHeaderBorder = Controls::Border{};
+    _paneHeaderBorder.Padding({ 0, 0, 0, 0 });
+    _paneHeaderBorder.Child(_paneHeaderText);
+    _paneHeaderBorder.Visibility(WUX::Visibility::Collapsed);
+}
+
+// Method Description:
+// - Sets up the leaf pane layout in _root: a header row (auto-sized) and a
+//   content row (star-sized). The TermControl stays as the direct child of
+//   _borderFirst so the SwapChainPanel renders correctly.
+void Pane::_SetupLeafLayout(const winrt::Windows::UI::Xaml::UIElement& control)
+{
+    auto headerRow = Controls::RowDefinition{};
+    headerRow.Height(GridLengthHelper::Auto());
+    auto contentRow = Controls::RowDefinition{};
+    contentRow.Height(GridLengthHelper::FromValueAndType(1, GridUnitType::Star));
+    _root.RowDefinitions().Append(headerRow);
+    _root.RowDefinitions().Append(contentRow);
+
+    Controls::Grid::SetRow(_paneHeaderBorder, 0);
+    Controls::Grid::SetRow(_borderFirst, 1);
+
+    _root.Children().Append(_paneHeaderBorder);
+    _root.Children().Append(_borderFirst);
+
+    if (control)
+    {
+        _borderFirst.Child(control);
+    }
+}
+
+// Method Description:
+// - Show or hide the pane header title bar on all leaf panes in the tree.
+//   Called by Tab when the number of panes changes.
+void Pane::ShowPaneHeaders(bool show)
+{
+    if (_IsLeaf())
+    {
+        if (_paneHeaderBorder)
+        {
+            namespace WUX = winrt::Windows::UI::Xaml;
+            _paneHeaderBorder.Visibility(show ? WUX::Visibility::Visible : WUX::Visibility::Collapsed);
+
+            if (show)
+            {
+                const auto& brush = _ComputeBorderColor();
+                _paneHeaderBorder.Background(brush);
+                _paneHeaderText.Foreground(winrt::Windows::UI::Xaml::Media::SolidColorBrush(winrt::Windows::UI::Colors::White()));
+            }
+        }
+    }
+    else
+    {
+        _firstChild->ShowPaneHeaders(show);
+        _secondChild->ShowPaneHeaders(show);
+    }
+}
+
+// Method Description:
+// - Sets up row/column definitions for this pane.There are three total
 //   row/cols. The middle one is for the separator. The first and third are for
 //   each of the child panes, and are given a size in pixels, based off the
 //   available space, and the percent of the space they respectively consume,
@@ -2321,6 +2416,10 @@ std::pair<std::shared_ptr<Pane>, std::shared_ptr<Pane>> Pane::_Split(SplitDirect
     _root.RowDefinitions().Clear();
     _CreateRowColDefinitions();
 
+    // Reset Grid.Row on _borderFirst — it may have been set to row 1 in the
+    // leaf layout (header=row0, content=row1).
+    Controls::Grid::SetRow(_borderFirst, 0);
+
     _borderFirst.Child(_firstChild->GetRootElement());
     _borderSecond.Child(_secondChild->GetRootElement());
 

src/cascadia/TerminalApp/Pane.h

@@ -150,6 +150,7 @@ class Pane : public std::enable_shared_from_this<Pane>
     bool ContainsReadOnly() const;
 
     void EnableBroadcast(bool enabled);
+    void ShowPaneHeaders(bool show);
     void BroadcastKey(const winrt::Microsoft::Terminal::Control::TermControl& sourceControl, const WORD vkey, const WORD scanCode, const winrt::Microsoft::Terminal::Core::ControlKeyStates modifiers, const bool keyDown);
     void BroadcastChar(const winrt::Microsoft::Terminal::Control::TermControl& sourceControl, const wchar_t vkey, const WORD scanCode, const winrt::Microsoft::Terminal::Core::ControlKeyStates modifiers);
     void BroadcastString(const winrt::Microsoft::Terminal::Control::TermControl& sourceControl, const winrt::hstring& text);
@@ -235,6 +236,11 @@ class Pane : public std::enable_shared_from_this<Pane>
     winrt::Windows::UI::Xaml::Controls::Border _borderFirst{};
     winrt::Windows::UI::Xaml::Controls::Border _borderSecond{};
 
+    // Per-pane title header (visible when there are split panes)
+    winrt::Windows::UI::Xaml::Controls::Border _paneHeaderBorder{ nullptr };
+    winrt::Windows::UI::Xaml::Controls::TextBlock _paneHeaderText{ nullptr };
+    winrt::TerminalApp::IPaneContent::TitleChanged_revoker _titleChangedRevoker;
+
     PaneResources _themeResources;
 
 #pragma region Properties that need to be transferred between child / parent panes upon splitting / closing
@@ -266,6 +272,8 @@ class Pane : public std::enable_shared_from_this<Pane>
     void _SetupChildCloseHandlers();
     winrt::TerminalApp::IPaneContent _takePaneContent();
     void _setPaneContent(winrt::TerminalApp::IPaneContent content);
+    void _CreatePaneHeader();
+    void _SetupLeafLayout(const winrt::Windows::UI::Xaml::UIElement& control);
     bool _HasChild(const std::shared_ptr<Pane> child);
     winrt::TerminalApp::TerminalPaneContent _getTerminalContent() const;
 

src/cascadia/TerminalApp/Tab.cpp

@@ -361,6 +361,10 @@ namespace winrt::TerminalApp::implementation
         // The tabWidthMode may have changed, update the header control accordingly
         _UpdateHeaderControlMaxWidth();
 
+        // Refresh pane header visibility based on the current setting
+        const auto showHeaders = settings.GlobalSettings().ShowPaneHeaders() && _rootPane->GetLeafPaneCount() > 1;
+        _rootPane->ShowPaneHeaders(showHeaders);
+
         // Update the settings on all our panes.
         _rootPane->WalkTree([&](const auto& pane) {
             pane->UpdateSettings(settings);
@@ -646,6 +650,14 @@ namespace winrt::TerminalApp::implementation
         // After split, Close Pane Menu Item should be visible
         _closePaneMenuItem.Visibility(WUX::Visibility::Visible);
 
+        // Show pane headers now that we have multiple panes (if the setting is enabled)
+        try
+        {
+            const auto settings{ winrt::TerminalApp::implementation::AppLogic::CurrentAppSettings() };
+            _rootPane->ShowPaneHeaders(settings.GlobalSettings().ShowPaneHeaders());
+        }
+        CATCH_LOG();
+
         // The active pane has an id if it is a leaf
         if (activePaneId)
         {
@@ -1324,6 +1336,7 @@ namespace winrt::TerminalApp::implementation
         if (_rootPane->GetLeafPaneCount() == 1)
         {
             _closePaneMenuItem.Visibility(WUX::Visibility::Collapsed);
+            _rootPane->ShowPaneHeaders(false);
         }
 
         _RecalculateAndApplyReadOnly();

src/cascadia/TerminalSettingsEditor/GlobalAppearance.xaml

@@ -75,6 +75,13 @@
                           Style="{StaticResource ToggleSwitchInExpanderStyle}" />
         </local:SettingContainer>
 
+        <!--  Show pane headers  -->
+        <local:SettingContainer x:Name="ShowPaneHeaders"
+                                x:Uid="Globals_ShowPaneHeaders">
+            <ToggleSwitch IsOn="{x:Bind ViewModel.ShowPaneHeaders, Mode=TwoWay}"
+                          Style="{StaticResource ToggleSwitchInExpanderStyle}" />
+        </local:SettingContainer>
+
         <!--  Show Acrylic in Tab Row  -->
         <local:SettingContainer x:Name="AcrylicTabRow"
                                 x:Uid="Globals_AcrylicTabRow">

src/cascadia/TerminalSettingsEditor/GlobalAppearanceViewModel.h

@@ -33,6 +33,7 @@ namespace winrt::Microsoft::Terminal::Settings::Editor::implementation
 
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, AlwaysShowTabs);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, ShowTabsFullscreen);
+        PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, ShowPaneHeaders);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, ShowTabsInTitlebar);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, UseAcrylicInTabRow);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(_GlobalSettings, ShowTitleInTitlebar);

src/cascadia/TerminalSettingsEditor/GlobalAppearanceViewModel.idl

@@ -27,6 +27,7 @@ namespace Microsoft.Terminal.Settings.Editor
 
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, AlwaysShowTabs);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, ShowTabsFullscreen);
+        PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, ShowPaneHeaders);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, ShowTabsInTitlebar);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, UseAcrylicInTabRow);
         PERMANENT_OBSERVABLE_PROJECTED_SETTING(Boolean, ShowTitleInTitlebar);

src/cascadia/TerminalSettingsEditor/Resources/en-US/Resources.resw

@@ -2593,6 +2593,14 @@
     <value>When enabled, the tab bar will be visible when the app is full screen.</value>
     <comment>A description for what the "show tabs in full screen" setting does.</comment>
   </data>
+  <data name="Globals_ShowPaneHeaders.Header" xml:space="preserve">
+    <value>Show pane title headers</value>
+    <comment>Header for a control to toggle if the app should show title headers above each pane when multiple panes are open.</comment>
+  </data>
+  <data name="Globals_ShowPaneHeaders.HelpText" xml:space="preserve">
+    <value>When enabled, a title header is shown above each pane when multiple panes are open.</value>
+    <comment>A description for what the "show pane headers" setting does. Presented near "Globals_ShowPaneHeaders.Header".</comment>
+  </data>
   <data name="Profile_PathTranslationStyle.[using:Windows.UI.Xaml.Automation]AutomationProperties.Name" xml:space="preserve">
     <value>Path translation</value>
     <comment>Name for a control to select how file and directory paths are translated.</comment>

src/cascadia/TerminalSettingsModel/GlobalAppSettings.idl

@@ -59,6 +59,7 @@ namespace Microsoft.Terminal.Settings.Model
         INHERITABLE_SETTING(Int32, InitialCols);
         INHERITABLE_SETTING(Boolean, AlwaysShowTabs);
         INHERITABLE_SETTING(Boolean, ShowTabsFullscreen);
+        INHERITABLE_SETTING(Boolean, ShowPaneHeaders);
         INHERITABLE_SETTING(NewTabPosition, NewTabPosition);
         INHERITABLE_SETTING(Boolean, ShowTitleInTitlebar);
         INHERITABLE_SETTING(Boolean, ConfirmCloseAllTabs);

src/cascadia/TerminalSettingsModel/MTSMSettings.h

@@ -71,7 +71,8 @@ Author(s):
     X(winrt::Windows::Foundation::Collections::IVector<Model::NewTabMenuEntry>, NewTabMenu, "newTabMenu", winrt::single_threaded_vector<Model::NewTabMenuEntry>({ Model::RemainingProfilesEntry{} })) \
     X(bool, AllowHeadless, "compatibility.allowHeadless", false)                                                                                                                                      \
     X(hstring, SearchWebDefaultQueryUrl, "searchWebDefaultQueryUrl", L"https://www.bing.com/search?q=%22%s%22")                                                                                       \
-    X(bool, ShowTabsFullscreen, "showTabsFullscreen", false)
+    X(bool, ShowTabsFullscreen, "showTabsFullscreen", false)                                                                                                                                          \
+    X(bool, ShowPaneHeaders, "showPaneHeaders", true)
 
 // Also add these settings to:
 // * Profile.idl