From 3b1a5e9418c7c3d90100c95743b30660081474d1 Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Wed, 11 Nov 2020 12:10:51 -0500
Subject: [PATCH 01/10] initial

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 28 ++++++++++++++++++
 src/cascadia/TerminalApp/TabHeaderControl.h   | 25 ++++++++++++++++
 src/cascadia/TerminalApp/TabHeaderControl.idl | 12 ++++++++
 .../TerminalApp/TabHeaderControl.xaml         | 29 +++++++++++++++++++
 .../TerminalApp/TerminalAppLib.vcxproj        | 13 +++++++++
 .../TerminalAppLib.vcxproj.filters            |  3 ++
 src/cascadia/TerminalApp/TerminalTab.cpp      | 18 +++---------
 src/cascadia/TerminalApp/TerminalTab.h        |  1 +
 8 files changed, 115 insertions(+), 14 deletions(-)
 create mode 100644 src/cascadia/TerminalApp/TabHeaderControl.cpp
 create mode 100644 src/cascadia/TerminalApp/TabHeaderControl.h
 create mode 100644 src/cascadia/TerminalApp/TabHeaderControl.idl
 create mode 100644 src/cascadia/TerminalApp/TabHeaderControl.xaml

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
new file mode 100644
index 00000000000..090fff877df
--- /dev/null
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "pch.h"
+#include "TabHeaderControl.h"
+
+#include "TabHeaderControl.g.cpp"
+
+using namespace winrt;
+using namespace winrt::Microsoft::UI::Xaml;
+
+namespace winrt::TerminalApp::implementation
+{
+    TabHeaderControl::TabHeaderControl()
+    {
+        InitializeComponent();
+    }
+
+    void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
+    {
+        HeaderTextBlock().Text(title);
+    }
+
+    void TabHeaderControl::SetZoomIcon(Windows::UI::Xaml::Visibility state)
+    {
+        HeaderZoomIcon().Visibility(state);
+    }
+}
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
new file mode 100644
index 00000000000..39494010211
--- /dev/null
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+#include "winrt/Microsoft.UI.Xaml.Controls.h"
+
+#include "TabHeaderControl.g.h"
+
+namespace winrt::TerminalApp::implementation
+{
+    struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
+    {
+        TabHeaderControl();
+        void UpdateHeaderText(winrt::hstring title);
+        void SetZoomIcon(Windows::UI::Xaml::Visibility state);
+    };
+}
+
+namespace winrt::TerminalApp::factory_implementation
+{
+    struct TabHeaderControl : TabHeaderControlT<TabHeaderControl, implementation::TabHeaderControl>
+    {
+    };
+}
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
new file mode 100644
index 00000000000..a516feb2e40
--- /dev/null
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+namespace TerminalApp
+{
+    [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl
+    {
+        TabHeaderControl();
+        void UpdateHeaderText(String title);
+        void SetZoomIcon(Windows.UI.Xaml.Visibility state);
+    }
+}
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.xaml b/src/cascadia/TerminalApp/TabHeaderControl.xaml
new file mode 100644
index 00000000000..ab7ce0c1b61
--- /dev/null
+++ b/src/cascadia/TerminalApp/TabHeaderControl.xaml
@@ -0,0 +1,29 @@
+<!-- Copyright (c) Microsoft Corporation. All rights reserved. Licensed under
+the MIT License. See LICENSE in the project root for license information. -->
+<UserControl
+    x:Class="TerminalApp.TabHeaderControl"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:TerminalApp"
+    xmlns:mux="using:Microsoft.UI.Xaml.Controls"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d">
+
+    <StackPanel x:Name="HeaderStackPanel"
+                Orientation="Horizontal">
+        <FontIcon x:Name="HeaderZoomIcon"
+                  FontFamily="Segoe MDL2 Assets"
+                  Visibility="Collapsed"
+                  Glyph="&#xE8A3;"
+                  FontSize="12"
+                  Margin="0,0,8,0"/>
+        <TextBlock x:Name="HeaderTextBlock"
+                   Visibility="Visible"/>
+        <TextBox x:Name="HeaderRenamerTextBox"
+                 Visibility="Collapsed"
+                 MinHeight="0"
+                 Padding="4,0,4,0"
+                 Margin="0,-8,0,-8"/>
+    </StackPanel>
+</UserControl>
diff --git a/src/cascadia/TerminalApp/TerminalAppLib.vcxproj b/src/cascadia/TerminalApp/TerminalAppLib.vcxproj
index f653d7d4264..bffa63b7acf 100644
--- a/src/cascadia/TerminalApp/TerminalAppLib.vcxproj
+++ b/src/cascadia/TerminalApp/TerminalAppLib.vcxproj
@@ -53,6 +53,9 @@
     </Page>
     <Page Include="TabRowControl.xaml">
       <SubType>Designer</SubType>
+    </Page>
+        <Page Include="TabHeaderControl.xaml">
+      <SubType>Designer</SubType>
     </Page>
     <Page Include="HighlightedTextControl.xaml">
       <SubType>Designer</SubType>
@@ -89,6 +92,9 @@
     <ClInclude Include="TabRowControl.h">
       <DependentUpon>TabRowControl.xaml</DependentUpon>
     </ClInclude>
+    <ClInclude Include="TabHeaderControl.h">
+      <DependentUpon>TabHeaderControl.xaml</DependentUpon>
+    </ClInclude>
     <ClInclude Include="HighlightedTextControl.h">
       <DependentUpon>HighlightedTextControl.xaml</DependentUpon>
     </ClInclude>
@@ -154,6 +160,9 @@
     <ClCompile Include="TabRowControl.cpp">
       <DependentUpon>TabRowControl.xaml</DependentUpon>
     </ClCompile>
+    <ClCompile Include="TabHeaderControl.cpp">
+      <DependentUpon>TabHeaderControl.xaml</DependentUpon>
+    </ClCompile>
     <ClCompile Include="HighlightedTextControl.cpp">
       <DependentUpon>HighlightedTextControl.xaml</DependentUpon>
     </ClCompile>
@@ -230,6 +239,10 @@
       <DependentUpon>TabRowControl.xaml</DependentUpon>
       <SubType>Code</SubType>
     </Midl>
+    <Midl Include="TabHeaderControl.idl">
+      <DependentUpon>TabHeaderControl.xaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Midl>
     <Midl Include="HighlightedTextControl.idl">
       <DependentUpon>HighlightedTextControl.xaml</DependentUpon>
       <SubType>Code</SubType>
diff --git a/src/cascadia/TerminalApp/TerminalAppLib.vcxproj.filters b/src/cascadia/TerminalApp/TerminalAppLib.vcxproj.filters
index 8f89e58292f..3d424c3996f 100644
--- a/src/cascadia/TerminalApp/TerminalAppLib.vcxproj.filters
+++ b/src/cascadia/TerminalApp/TerminalAppLib.vcxproj.filters
@@ -106,6 +106,9 @@
     <Page Include="TabRowControl.xaml">
       <Filter>controls</Filter>
     </Page>
+    <Page Include="TabHeaderControl.xaml">
+      <Filter>controls</Filter>
+    </Page>
     <Page Include="TerminalPage.xaml">
       <Filter>controls</Filter>
     </Page>
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index 567d48a7ba1..d15bf04972a 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -37,6 +37,7 @@ namespace winrt::TerminalApp::implementation
 
         _MakeTabViewItem();
         _CreateContextMenu();
+        TabViewItem().Header(_headerControl);
     }
 
     // Method Description:
@@ -589,26 +590,15 @@ namespace winrt::TerminalApp::implementation
         {
             if (_zoomedPane)
             {
-                Controls::StackPanel sp;
-                sp.Orientation(Controls::Orientation::Horizontal);
-                Controls::FontIcon ico;
-                ico.FontFamily(Media::FontFamily{ L"Segoe MDL2 Assets" });
-                ico.Glyph(L"\xE8A3"); // "ZoomIn", a magnifying glass with a '+' in it.
-                ico.FontSize(12);
-                ico.Margin(ThicknessHelper::FromLengths(0, 0, 8, 0));
-                sp.Children().Append(ico);
-                Controls::TextBlock tb;
-                tb.Text(tabText);
-                sp.Children().Append(tb);
-
-                TabViewItem().Header(sp);
+                _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Visible);
             }
             else
             {
                 // If we're not currently in the process of renaming the tab,
                 // then just set the tab's text to whatever our active title is.
-                TabViewItem().Header(winrt::box_value(tabText));
+                _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Collapsed);
             }
+            _headerControl.UpdateHeaderText(tabText);
         }
         else
         {
diff --git a/src/cascadia/TerminalApp/TerminalTab.h b/src/cascadia/TerminalApp/TerminalTab.h
index 7144a961fa4..fc8ad5f6590 100644
--- a/src/cascadia/TerminalApp/TerminalTab.h
+++ b/src/cascadia/TerminalApp/TerminalTab.h
@@ -80,6 +80,7 @@ namespace winrt::TerminalApp::implementation
         std::optional<winrt::Windows::UI::Color> _runtimeTabColor{};
         winrt::Windows::UI::Xaml::Controls::MenuFlyoutItem _closeOtherTabsMenuItem{};
         winrt::Windows::UI::Xaml::Controls::MenuFlyoutItem _closeTabsAfterMenuItem{};
+        winrt::TerminalApp::TabHeaderControl _headerControl{};
 
         bool _receivedKeyDown{ false };
 

From 40c692046f73010fe403e25a05e8c9229925b2bf Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Wed, 11 Nov 2020 15:42:01 -0500
Subject: [PATCH 02/10] rename box

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp |  48 ++++++
 src/cascadia/TerminalApp/TabHeaderControl.h   |   8 +
 src/cascadia/TerminalApp/TabHeaderControl.idl |   1 +
 .../TerminalApp/TabHeaderControl.xaml         |   3 +-
 src/cascadia/TerminalApp/TerminalTab.cpp      | 157 +-----------------
 src/cascadia/TerminalApp/TerminalTab.h        |   2 -
 6 files changed, 63 insertions(+), 156 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 090fff877df..8dfe3a6f0a5 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -14,6 +14,28 @@ namespace winrt::TerminalApp::implementation
     TabHeaderControl::TabHeaderControl()
     {
         InitializeComponent();
+
+        HeaderRenamerTextBox().KeyDown([&](auto&&, auto&&) {
+            _receivedKeyDown = true;
+        });
+
+        HeaderRenamerTextBox().KeyUp([&](auto&&, Windows::UI::Xaml::Input::KeyRoutedEventArgs const& e) {
+            if (_receivedKeyDown)
+            {
+                if (e.OriginalKey() == Windows::System::VirtualKey::Enter)
+                {
+                    // close the rename box
+                    _CloseRenameBox();
+                }
+                else if (e.OriginalKey() == Windows::System::VirtualKey::Escape)
+                {
+                    // the user wants to discard the changes they made,
+                    // reset the rename box text to the old text and close the rename box
+                    HeaderRenamerTextBox().Text(HeaderTextBlock().Text());
+                    _CloseRenameBox();
+                }
+            }
+        });
     }
 
     void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
@@ -25,4 +47,30 @@ namespace winrt::TerminalApp::implementation
     {
         HeaderZoomIcon().Visibility(state);
     }
+
+    void TabHeaderControl::ConstructTabRenameBox()
+    {
+        _receivedKeyDown = false;
+
+        HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
+        HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Visible);
+
+        HeaderRenamerTextBox().Text(HeaderTextBlock().Text());
+        HeaderRenamerTextBox().SelectAll();
+        HeaderRenamerTextBox().Focus(Windows::UI::Xaml::FocusState::Programmatic);
+    }
+
+    void TabHeaderControl::RenameBoxLostFocusHandler(Windows::Foundation::IInspectable const& /*sender*/,
+                                                     Windows::UI::Xaml::RoutedEventArgs const& /*e*/)
+    {
+        _CloseRenameBox();
+    }
+
+    void TabHeaderControl::_CloseRenameBox()
+    {
+        HeaderTextBlock().Text(HeaderRenamerTextBox().Text());
+
+        HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
+        HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
+    }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 39494010211..7ca487a86db 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -14,6 +14,14 @@ namespace winrt::TerminalApp::implementation
         TabHeaderControl();
         void UpdateHeaderText(winrt::hstring title);
         void SetZoomIcon(Windows::UI::Xaml::Visibility state);
+        void ConstructTabRenameBox();
+
+        void RenameBoxLostFocusHandler(winrt::Windows::Foundation::IInspectable const& sender,
+                                       winrt::Windows::UI::Xaml::RoutedEventArgs const& e);
+
+    private:
+        void _CloseRenameBox();
+        bool _receivedKeyDown{ false };
     };
 }
 
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index a516feb2e40..598abb18835 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -8,5 +8,6 @@ namespace TerminalApp
         TabHeaderControl();
         void UpdateHeaderText(String title);
         void SetZoomIcon(Windows.UI.Xaml.Visibility state);
+        void ConstructTabRenameBox();
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.xaml b/src/cascadia/TerminalApp/TabHeaderControl.xaml
index ab7ce0c1b61..574e1502a8b 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.xaml
+++ b/src/cascadia/TerminalApp/TabHeaderControl.xaml
@@ -24,6 +24,7 @@ the MIT License. See LICENSE in the project root for license information. -->
                  Visibility="Collapsed"
                  MinHeight="0"
                  Padding="4,0,4,0"
-                 Margin="0,-8,0,-8"/>
+                 Margin="0,-8,0,-8"
+                 LostFocus="RenameBoxLostFocusHandler"/>
     </StackPanel>
 </UserControl>
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index d15bf04972a..f9b8363953d 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -218,7 +218,7 @@ namespace winrt::TerminalApp::implementation
             SwitchToTabCommand().Name(Title());
 
             // Update the UI to reflect the changed
-            _UpdateTabHeader();
+            _headerControl.UpdateHeaderText(Title());
         }
     }
 
@@ -368,9 +368,7 @@ namespace winrt::TerminalApp::implementation
     // - <none>
     void TerminalTab::ActivateTabRenamer()
     {
-        _inRename = true;
-        _receivedKeyDown = false;
-        _UpdateTabHeader();
+        _headerControl.ConstructTabRenameBox();
     }
 
     // Method Description:
@@ -570,153 +568,6 @@ namespace winrt::TerminalApp::implementation
         TabViewItem().ContextFlyout(newTabFlyout);
     }
 
-    // Method Description:
-    // - This will update the contents of our TabViewItem for our current state.
-    //   - If we're not in a rename, we'll set the Header of the TabViewItem to
-    //     simply our current tab text (either the runtime tab text or the
-    //     active terminal's text).
-    //   - If we're in a rename, then we'll set the Header to a TextBox with the
-    //     current tab text. The user can then use that TextBox to set a string
-    //     to use as an override for the tab's text.
-    // Arguments:
-    // - <none>
-    // Return Value:
-    // - <none>
-    void TerminalTab::_UpdateTabHeader()
-    {
-        winrt::hstring tabText{ Title() };
-
-        if (!_inRename)
-        {
-            if (_zoomedPane)
-            {
-                _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Visible);
-            }
-            else
-            {
-                // If we're not currently in the process of renaming the tab,
-                // then just set the tab's text to whatever our active title is.
-                _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Collapsed);
-            }
-            _headerControl.UpdateHeaderText(tabText);
-        }
-        else
-        {
-            _ConstructTabRenameBox(tabText);
-        }
-    }
-
-    // Method Description:
-    // - Create a new TextBox to use as the control for renaming the tab text.
-    //   If the text box is already created, then this will do nothing, and
-    //   leave the current box unmodified.
-    // Arguments:
-    // - tabText: This should be the text to initialize the rename text box with.
-    // Return Value:
-    // - <none>
-    void TerminalTab::_ConstructTabRenameBox(const winrt::hstring& tabText)
-    {
-        if (TabViewItem().Header().try_as<Controls::TextBox>())
-        {
-            return;
-        }
-
-        Controls::TextBox tabTextBox;
-        tabTextBox.Text(tabText);
-
-        // The TextBox has a MinHeight already set by default, which is
-        // larger than we want. Get rid of it.
-        tabTextBox.MinHeight(0);
-        // Also get rid of the internal padding on the text box, between the
-        // border and the text content, on the top and bottom. This will
-        // help the box fit within the bounds of the tab.
-        Thickness internalPadding = ThicknessHelper::FromLengths(4, 0, 4, 0);
-        tabTextBox.Padding(internalPadding);
-
-        // Make the margin (0, -8, 0, -8), to counteract the padding that
-        // the TabViewItem has.
-        //
-        // This is maybe a bit fragile, as the actual value might not be exactly
-        // (0, 8, 0, 8), but using TabViewItemHeaderPadding to look up the real
-        // value at runtime didn't work. So this is good enough for now.
-        Thickness negativeMargins = ThicknessHelper::FromLengths(0, -8, 0, -8);
-        tabTextBox.Margin(negativeMargins);
-
-        // Set up some event handlers on the text box. We need three of them:
-        // * A LostFocus event, so when the TextBox loses focus, we'll
-        //   remove it and return to just the text on the tab.
-        // * A KeyUp event, to be able to submit the tab text on Enter or
-        //   dismiss the text box on Escape
-        // * A LayoutUpdated event, so that we can auto-focus the text box
-        //   when it's added to the tree.
-        auto weakThis{ get_weak() };
-
-        // When the text box loses focus, update the tab title of our tab.
-        // - If there are any contents in the box, we'll use that value as
-        //   the new "runtime text", which will override any text set by the
-        //   application.
-        // - If the text box is empty, we'll reset the "runtime text", and
-        //   return to using the active terminal's title.
-        tabTextBox.LostFocus([weakThis](const IInspectable& sender, auto&&) {
-            auto tab{ weakThis.get() };
-            auto textBox{ sender.try_as<Controls::TextBox>() };
-            if (tab && textBox)
-            {
-                tab->_runtimeTabText = textBox.Text();
-                tab->_inRename = false;
-                tab->UpdateTitle();
-            }
-        });
-
-        // We'll only process the KeyUp event if we received an initial KeyDown event first.
-        // Avoids issue immediately closing the tab rename when we see the enter KeyUp event that was
-        // sent to the command palette to trigger the openTabRenamer action in the first place.
-        tabTextBox.KeyDown([weakThis](const IInspectable&, Input::KeyRoutedEventArgs const&) {
-            auto tab{ weakThis.get() };
-            tab->_receivedKeyDown = true;
-        });
-
-        // NOTE: (Preview)KeyDown does not work here. If you use that, we'll
-        // remove the TextBox from the UI tree, then the following KeyUp
-        // will bubble to the NewTabButton, which we don't want to have
-        // happen.
-        tabTextBox.KeyUp([weakThis](const IInspectable& sender, Input::KeyRoutedEventArgs const& e) {
-            auto tab{ weakThis.get() };
-            auto textBox{ sender.try_as<Controls::TextBox>() };
-            if (tab && textBox && tab->_receivedKeyDown)
-            {
-                switch (e.OriginalKey())
-                {
-                case VirtualKey::Enter:
-                    tab->_runtimeTabText = textBox.Text();
-                    [[fallthrough]];
-                case VirtualKey::Escape:
-                    e.Handled(true);
-                    textBox.Text(tab->_runtimeTabText);
-                    tab->_inRename = false;
-                    tab->UpdateTitle();
-                    break;
-                }
-            }
-        });
-
-        // As soon as the text box is added to the UI tree, focus it. We can't focus it till it's in the tree.
-        _tabRenameBoxLayoutUpdatedRevoker = tabTextBox.LayoutUpdated(winrt::auto_revoke, [this](auto&&, auto&&) {
-            // Curiously, the sender for this event is null, so we have to
-            // get the TextBox from the Tab's Header().
-            auto textBox{ TabViewItem().Header().try_as<Controls::TextBox>() };
-            if (textBox)
-            {
-                textBox.SelectAll();
-                textBox.Focus(FocusState::Programmatic);
-            }
-            // Only let this succeed once.
-            _tabRenameBoxLayoutUpdatedRevoker.revoke();
-        });
-
-        TabViewItem().Header(tabTextBox);
-    }
-
     // Method Description:
     // Returns the tab color, if any
     // Arguments:
@@ -989,7 +840,7 @@ namespace winrt::TerminalApp::implementation
         _zoomedPane = _activePane;
         _rootPane->Maximize(_zoomedPane);
         // Update the tab header to show the magnifying glass
-        _UpdateTabHeader();
+        _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Visible);
         Content(_zoomedPane->GetRootElement());
     }
     void TerminalTab::ExitZoom()
@@ -997,7 +848,7 @@ namespace winrt::TerminalApp::implementation
         _rootPane->Restore(_zoomedPane);
         _zoomedPane = nullptr;
         // Update the tab header to hide the magnifying glass
-        _UpdateTabHeader();
+        _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Collapsed);
         Content(_rootPane->GetRootElement());
     }
 
diff --git a/src/cascadia/TerminalApp/TerminalTab.h b/src/cascadia/TerminalApp/TerminalTab.h
index fc8ad5f6590..ae176d44663 100644
--- a/src/cascadia/TerminalApp/TerminalTab.h
+++ b/src/cascadia/TerminalApp/TerminalTab.h
@@ -104,8 +104,6 @@ namespace winrt::TerminalApp::implementation
         void _UpdateActivePane(std::shared_ptr<Pane> pane);
 
         winrt::hstring _GetActiveTitle() const;
-        void _UpdateTabHeader();
-        void _ConstructTabRenameBox(const winrt::hstring& tabText);
 
         void _RecalculateAndApplyTabColor();
         void _ApplyTabColor(const winrt::Windows::UI::Color& color);

From 52cc864e790f4e6cd86d8f576b274010186e4fec Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Wed, 11 Nov 2020 17:14:44 -0500
Subject: [PATCH 03/10] inform hosting tab when title changes, comments

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 38 ++++++++++++++++++-
 src/cascadia/TerminalApp/TabHeaderControl.h   |  4 ++
 src/cascadia/TerminalApp/TabHeaderControl.idl |  5 +++
 src/cascadia/TerminalApp/TerminalTab.cpp      | 12 +++++-
 4 files changed, 56 insertions(+), 3 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 8dfe3a6f0a5..8607741ace0 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -15,21 +15,28 @@ namespace winrt::TerminalApp::implementation
     {
         InitializeComponent();
 
+        // We'll only process the KeyUp event if we received an initial KeyDown event first.
+        // Avoids issue immediately closing the tab rename when we see the enter KeyUp event that was
+        // sent to the command palette to trigger the openTabRenamer action in the first place.
         HeaderRenamerTextBox().KeyDown([&](auto&&, auto&&) {
             _receivedKeyDown = true;
         });
 
+        // NOTE: (Preview)KeyDown does not work here. If you use that, we'll
+        // remove the TextBox from the UI tree, then the following KeyUp
+        // will bubble to the NewTabButton, which we don't want to have
+        // happen.
         HeaderRenamerTextBox().KeyUp([&](auto&&, Windows::UI::Xaml::Input::KeyRoutedEventArgs const& e) {
             if (_receivedKeyDown)
             {
                 if (e.OriginalKey() == Windows::System::VirtualKey::Enter)
                 {
-                    // close the rename box
+                    // User is done making changes, close the rename box
                     _CloseRenameBox();
                 }
                 else if (e.OriginalKey() == Windows::System::VirtualKey::Escape)
                 {
-                    // the user wants to discard the changes they made,
+                    // User wants to discard the changes they made,
                     // reset the rename box text to the old text and close the rename box
                     HeaderRenamerTextBox().Text(HeaderTextBlock().Text());
                     _CloseRenameBox();
@@ -38,16 +45,36 @@ namespace winrt::TerminalApp::implementation
         });
     }
 
+    // Method Description
+    // - Retrives the current title
+    // Return Value:
+    // - The current title as a winrt hstring
+    winrt::hstring TabHeaderControl::CurrentHeaderText()
+    {
+        return HeaderTextBlock().Text();
+    }
+
+    // Method Description
+    // - Updates the current title
+    // Arguments:
+    // - The desired title
     void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
     {
         HeaderTextBlock().Text(title);
     }
 
+    // Method Description:
+    // - Updates the zoom icon indicating whether a pane is zoomed
+    // Arguments:
+    // - The desired visibility state of the zoom icon
     void TabHeaderControl::SetZoomIcon(Windows::UI::Xaml::Visibility state)
     {
         HeaderZoomIcon().Visibility(state);
     }
 
+    // Method Description:
+    // - Show the tab rename box for the user to rename the tab title
+    // - We automatically use the previous title as the initial text of the box
     void TabHeaderControl::ConstructTabRenameBox()
     {
         _receivedKeyDown = false;
@@ -60,17 +87,24 @@ namespace winrt::TerminalApp::implementation
         HeaderRenamerTextBox().Focus(Windows::UI::Xaml::FocusState::Programmatic);
     }
 
+    // Method Description:
+    // - Event handler for when the rename box loses focus
     void TabHeaderControl::RenameBoxLostFocusHandler(Windows::Foundation::IInspectable const& /*sender*/,
                                                      Windows::UI::Xaml::RoutedEventArgs const& /*e*/)
     {
         _CloseRenameBox();
     }
 
+    // Method Description:
+    // - Hides the rename box and displays the title text block
+    // - Updates the title text block with the rename box's text
     void TabHeaderControl::_CloseRenameBox()
     {
         HeaderTextBlock().Text(HeaderRenamerTextBox().Text());
 
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
+
+        _HeaderTitleChangedHandlers();
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 7ca487a86db..6f8aacc2e84 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -4,6 +4,7 @@
 #pragma once
 
 #include "winrt/Microsoft.UI.Xaml.Controls.h"
+#include "inc/cppwinrt_utils.h"
 
 #include "TabHeaderControl.g.h"
 
@@ -12,6 +13,7 @@ namespace winrt::TerminalApp::implementation
     struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
     {
         TabHeaderControl();
+        winrt::hstring CurrentHeaderText();
         void UpdateHeaderText(winrt::hstring title);
         void SetZoomIcon(Windows::UI::Xaml::Visibility state);
         void ConstructTabRenameBox();
@@ -19,6 +21,8 @@ namespace winrt::TerminalApp::implementation
         void RenameBoxLostFocusHandler(winrt::Windows::Foundation::IInspectable const& sender,
                                        winrt::Windows::UI::Xaml::RoutedEventArgs const& e);
 
+        WINRT_CALLBACK(HeaderTitleChanged, TerminalApp::HeaderTitleChangedArgs);
+
     private:
         void _CloseRenameBox();
         bool _receivedKeyDown{ false };
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index 598abb18835..06a04ddc7ab 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -3,11 +3,16 @@
 
 namespace TerminalApp
 {
+    delegate void HeaderTitleChangedArgs();
+
     [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl
     {
         TabHeaderControl();
+        String CurrentHeaderText();
         void UpdateHeaderText(String title);
         void SetZoomIcon(Windows.UI.Xaml.Visibility state);
         void ConstructTabRenameBox();
+
+        event HeaderTitleChangedArgs HeaderTitleChanged;
     }
 }
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index f9b8363953d..c27c179895b 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -37,6 +37,16 @@ namespace winrt::TerminalApp::implementation
 
         _MakeTabViewItem();
         _CreateContextMenu();
+
+        // Add an event handler for the header control to tell us when the title changes
+        _headerControl.HeaderTitleChanged([weakThis = get_weak()]() {
+            if (auto tab{ weakThis.get() })
+            {
+                tab->SetTabText(tab->_headerControl.CurrentHeaderText());
+            }
+        });
+
+        // Use our header control as the TabViewItem's header
         TabViewItem().Header(_headerControl);
     }
 
@@ -217,7 +227,7 @@ namespace winrt::TerminalApp::implementation
             // Update SwitchToTab command's name
             SwitchToTabCommand().Name(Title());
 
-            // Update the UI to reflect the changed
+            // Update the control to reflect the changed title
             _headerControl.UpdateHeaderText(Title());
         }
     }

From e37b2257112c416d3330741cb1f1b420da5f4e7a Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Wed, 11 Nov 2020 17:19:29 -0500
Subject: [PATCH 04/10] spell

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 8607741ace0..f0a2e0069f0 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -46,7 +46,7 @@ namespace winrt::TerminalApp::implementation
     }
 
     // Method Description
-    // - Retrives the current title
+    // - Retrieves the current title
     // Return Value:
     // - The current title as a winrt hstring
     winrt::hstring TabHeaderControl::CurrentHeaderText()

From 613efc5903a21b2d973141ff1a270790ccbe485c Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Fri, 13 Nov 2020 11:16:22 -0500
Subject: [PATCH 05/10] store current title

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 11 ++++++-----
 src/cascadia/TerminalApp/TabHeaderControl.h   |  4 +++-
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index f0a2e0069f0..c6203f25655 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -38,7 +38,7 @@ namespace winrt::TerminalApp::implementation
                 {
                     // User wants to discard the changes they made,
                     // reset the rename box text to the old text and close the rename box
-                    HeaderRenamerTextBox().Text(HeaderTextBlock().Text());
+                    HeaderRenamerTextBox().Text(_currentTitle);
                     _CloseRenameBox();
                 }
             }
@@ -51,7 +51,7 @@ namespace winrt::TerminalApp::implementation
     // - The current title as a winrt hstring
     winrt::hstring TabHeaderControl::CurrentHeaderText()
     {
-        return HeaderTextBlock().Text();
+        return _currentTitle;
     }
 
     // Method Description
@@ -60,7 +60,8 @@ namespace winrt::TerminalApp::implementation
     // - The desired title
     void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
     {
-        HeaderTextBlock().Text(title);
+        _currentTitle = title;
+        HeaderTextBlock().Text(_currentTitle);
     }
 
     // Method Description:
@@ -82,7 +83,7 @@ namespace winrt::TerminalApp::implementation
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Visible);
 
-        HeaderRenamerTextBox().Text(HeaderTextBlock().Text());
+        HeaderRenamerTextBox().Text(_currentTitle);
         HeaderRenamerTextBox().SelectAll();
         HeaderRenamerTextBox().Focus(Windows::UI::Xaml::FocusState::Programmatic);
     }
@@ -100,7 +101,7 @@ namespace winrt::TerminalApp::implementation
     // - Updates the title text block with the rename box's text
     void TabHeaderControl::_CloseRenameBox()
     {
-        HeaderTextBlock().Text(HeaderRenamerTextBox().Text());
+        UpdateHeaderText(HeaderRenamerTextBox().Text());
 
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 6f8aacc2e84..8afd99c821e 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -24,8 +24,10 @@ namespace winrt::TerminalApp::implementation
         WINRT_CALLBACK(HeaderTitleChanged, TerminalApp::HeaderTitleChangedArgs);
 
     private:
-        void _CloseRenameBox();
+        winrt::hstring _currentTitle;
         bool _receivedKeyDown{ false };
+
+        void _CloseRenameBox();
     };
 }
 

From 01243cc562718ce259fc7e548ea67a5e8f5d5a11 Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Mon, 16 Nov 2020 11:23:42 -0500
Subject: [PATCH 06/10] send event to tab for them to update our title

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 26 ++++++-------------
 src/cascadia/TerminalApp/TabHeaderControl.h   |  5 ++--
 src/cascadia/TerminalApp/TabHeaderControl.idl |  5 ++--
 .../TerminalApp/TabHeaderControl.xaml         |  3 ++-
 src/cascadia/TerminalApp/TerminalTab.cpp      |  6 ++---
 5 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index c6203f25655..40cccfc9e3a 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -38,7 +38,7 @@ namespace winrt::TerminalApp::implementation
                 {
                     // User wants to discard the changes they made,
                     // reset the rename box text to the old text and close the rename box
-                    HeaderRenamerTextBox().Text(_currentTitle);
+                    HeaderRenamerTextBox().Text(Title());
                     _CloseRenameBox();
                 }
             }
@@ -46,22 +46,12 @@ namespace winrt::TerminalApp::implementation
     }
 
     // Method Description
-    // - Retrieves the current title
-    // Return Value:
-    // - The current title as a winrt hstring
-    winrt::hstring TabHeaderControl::CurrentHeaderText()
-    {
-        return _currentTitle;
-    }
-
-    // Method Description
-    // - Updates the current title
+    // - Updates the current title and bubbles the event up to the UI
     // Arguments:
     // - The desired title
     void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
     {
-        _currentTitle = title;
-        HeaderTextBlock().Text(_currentTitle);
+        Title(title);
     }
 
     // Method Description:
@@ -83,7 +73,7 @@ namespace winrt::TerminalApp::implementation
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Visible);
 
-        HeaderRenamerTextBox().Text(_currentTitle);
+        HeaderRenamerTextBox().Text(Title());
         HeaderRenamerTextBox().SelectAll();
         HeaderRenamerTextBox().Focus(Windows::UI::Xaml::FocusState::Programmatic);
     }
@@ -98,14 +88,14 @@ namespace winrt::TerminalApp::implementation
 
     // Method Description:
     // - Hides the rename box and displays the title text block
-    // - Updates the title text block with the rename box's text
+    // - Sends an event to the hosting tab to let them know we wish to change the title
+    //   to whatever is in the renamer box right now - the tab will process that event
+    //   and tell us to update our title
     void TabHeaderControl::_CloseRenameBox()
     {
-        UpdateHeaderText(HeaderRenamerTextBox().Text());
-
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
 
-        _HeaderTitleChangedHandlers();
+        _HeaderTitleChangedHandlers(HeaderRenamerTextBox().Text());
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 8afd99c821e..2b25049d33b 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -13,7 +13,6 @@ namespace winrt::TerminalApp::implementation
     struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
     {
         TabHeaderControl();
-        winrt::hstring CurrentHeaderText();
         void UpdateHeaderText(winrt::hstring title);
         void SetZoomIcon(Windows::UI::Xaml::Visibility state);
         void ConstructTabRenameBox();
@@ -23,8 +22,10 @@ namespace winrt::TerminalApp::implementation
 
         WINRT_CALLBACK(HeaderTitleChanged, TerminalApp::HeaderTitleChangedArgs);
 
+        WINRT_CALLBACK(PropertyChanged, Windows::UI::Xaml::Data::PropertyChangedEventHandler);
+        OBSERVABLE_GETSET_PROPERTY(winrt::hstring, Title, _PropertyChangedHandlers);
+
     private:
-        winrt::hstring _currentTitle;
         bool _receivedKeyDown{ false };
 
         void _CloseRenameBox();
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index 06a04ddc7ab..b2224d34a1e 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -3,12 +3,13 @@
 
 namespace TerminalApp
 {
-    delegate void HeaderTitleChangedArgs();
+    delegate void HeaderTitleChangedArgs(String title);
 
     [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl
     {
+        String Title { get; };
+
         TabHeaderControl();
-        String CurrentHeaderText();
         void UpdateHeaderText(String title);
         void SetZoomIcon(Windows.UI.Xaml.Visibility state);
         void ConstructTabRenameBox();
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.xaml b/src/cascadia/TerminalApp/TabHeaderControl.xaml
index 574e1502a8b..6b6041f0fce 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.xaml
+++ b/src/cascadia/TerminalApp/TabHeaderControl.xaml
@@ -19,7 +19,8 @@ the MIT License. See LICENSE in the project root for license information. -->
                   FontSize="12"
                   Margin="0,0,8,0"/>
         <TextBlock x:Name="HeaderTextBlock"
-                   Visibility="Visible"/>
+                   Visibility="Visible"
+                   Text="{x:Bind Title}"/>
         <TextBox x:Name="HeaderRenamerTextBox"
                  Visibility="Collapsed"
                  MinHeight="0"
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index c27c179895b..8dbbed98b46 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -38,11 +38,11 @@ namespace winrt::TerminalApp::implementation
         _MakeTabViewItem();
         _CreateContextMenu();
 
-        // Add an event handler for the header control to tell us when the title changes
-        _headerControl.HeaderTitleChanged([weakThis = get_weak()]() {
+        // Add an event handler for the header control to tell us when they want their title to change
+        _headerControl.HeaderTitleChanged([weakThis = get_weak()](auto&& title) {
             if (auto tab{ weakThis.get() })
             {
-                tab->SetTabText(tab->_headerControl.CurrentHeaderText());
+                tab->SetTabText(title);
             }
         });
 

From 4ef5fda069deef8bf8df3b578f92e805f3341bbe Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Mon, 16 Nov 2020 13:53:21 -0500
Subject: [PATCH 07/10] address comments

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp  | 9 ---------
 src/cascadia/TerminalApp/TabHeaderControl.h    | 1 -
 src/cascadia/TerminalApp/TabHeaderControl.idl  | 5 ++---
 src/cascadia/TerminalApp/TabHeaderControl.xaml | 2 +-
 src/cascadia/TerminalApp/TerminalTab.cpp       | 5 +++--
 5 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 40cccfc9e3a..b401b69361c 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -45,15 +45,6 @@ namespace winrt::TerminalApp::implementation
         });
     }
 
-    // Method Description
-    // - Updates the current title and bubbles the event up to the UI
-    // Arguments:
-    // - The desired title
-    void TabHeaderControl::UpdateHeaderText(winrt::hstring title)
-    {
-        Title(title);
-    }
-
     // Method Description:
     // - Updates the zoom icon indicating whether a pane is zoomed
     // Arguments:
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 2b25049d33b..547f4d4c0a4 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -13,7 +13,6 @@ namespace winrt::TerminalApp::implementation
     struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
     {
         TabHeaderControl();
-        void UpdateHeaderText(winrt::hstring title);
         void SetZoomIcon(Windows::UI::Xaml::Visibility state);
         void ConstructTabRenameBox();
 
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index b2224d34a1e..247ea9e120c 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -5,12 +5,11 @@ namespace TerminalApp
 {
     delegate void HeaderTitleChangedArgs(String title);
 
-    [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl
+    [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl, Windows.UI.Xaml.Data.INotifyPropertyChanged
     {
-        String Title { get; };
+        String Title { get; set; };
 
         TabHeaderControl();
-        void UpdateHeaderText(String title);
         void SetZoomIcon(Windows.UI.Xaml.Visibility state);
         void ConstructTabRenameBox();
 
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.xaml b/src/cascadia/TerminalApp/TabHeaderControl.xaml
index 6b6041f0fce..1656e32111e 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.xaml
+++ b/src/cascadia/TerminalApp/TabHeaderControl.xaml
@@ -20,7 +20,7 @@ the MIT License. See LICENSE in the project root for license information. -->
                   Margin="0,0,8,0"/>
         <TextBlock x:Name="HeaderTextBlock"
                    Visibility="Visible"
-                   Text="{x:Bind Title}"/>
+                   Text="{x:Bind Title, Mode=OneWay}"/>
         <TextBox x:Name="HeaderRenamerTextBox"
                  Visibility="Collapsed"
                  MinHeight="0"
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index 8dbbed98b46..aa3c3de6cfb 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -221,14 +221,15 @@ namespace winrt::TerminalApp::implementation
         co_await winrt::resume_foreground(TabViewItem().Dispatcher());
         if (auto tab{ weakThis.get() })
         {
+            const auto activeTitle = _GetActiveTitle();
             // Bubble our current tab text to anyone who's listening for changes.
-            Title(_GetActiveTitle());
+            Title(activeTitle);
 
             // Update SwitchToTab command's name
             SwitchToTabCommand().Name(Title());
 
             // Update the control to reflect the changed title
-            _headerControl.UpdateHeaderText(Title());
+            _headerControl.Title(activeTitle);
         }
     }
 

From 83a02f1b161e5c4e7cbc0cf5a493125b8571d39d Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Mon, 16 Nov 2020 13:56:39 -0500
Subject: [PATCH 08/10] rename event

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 2 +-
 src/cascadia/TerminalApp/TabHeaderControl.h   | 2 +-
 src/cascadia/TerminalApp/TabHeaderControl.idl | 4 ++--
 src/cascadia/TerminalApp/TerminalTab.cpp      | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index b401b69361c..8487cd046b0 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -87,6 +87,6 @@ namespace winrt::TerminalApp::implementation
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
 
-        _HeaderTitleChangedHandlers(HeaderRenamerTextBox().Text());
+        _HeaderTitleWantsToChangeHandlers(HeaderRenamerTextBox().Text());
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 547f4d4c0a4..7ad19cb7f2d 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -19,7 +19,7 @@ namespace winrt::TerminalApp::implementation
         void RenameBoxLostFocusHandler(winrt::Windows::Foundation::IInspectable const& sender,
                                        winrt::Windows::UI::Xaml::RoutedEventArgs const& e);
 
-        WINRT_CALLBACK(HeaderTitleChanged, TerminalApp::HeaderTitleChangedArgs);
+        WINRT_CALLBACK(HeaderTitleWantsToChange, TerminalApp::HeaderTitleWantsToChangeArgs);
 
         WINRT_CALLBACK(PropertyChanged, Windows::UI::Xaml::Data::PropertyChangedEventHandler);
         OBSERVABLE_GETSET_PROPERTY(winrt::hstring, Title, _PropertyChangedHandlers);
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index 247ea9e120c..d13e9a734dc 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -3,7 +3,7 @@
 
 namespace TerminalApp
 {
-    delegate void HeaderTitleChangedArgs(String title);
+    delegate void HeaderTitleWantsToChangeArgs(String title);
 
     [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl, Windows.UI.Xaml.Data.INotifyPropertyChanged
     {
@@ -13,6 +13,6 @@ namespace TerminalApp
         void SetZoomIcon(Windows.UI.Xaml.Visibility state);
         void ConstructTabRenameBox();
 
-        event HeaderTitleChangedArgs HeaderTitleChanged;
+        event HeaderTitleWantsToChangeArgs HeaderTitleWantsToChange;
     }
 }
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index aa3c3de6cfb..37c327688e0 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -39,7 +39,7 @@ namespace winrt::TerminalApp::implementation
         _CreateContextMenu();
 
         // Add an event handler for the header control to tell us when they want their title to change
-        _headerControl.HeaderTitleChanged([weakThis = get_weak()](auto&& title) {
+        _headerControl.HeaderTitleWantsToChange([weakThis = get_weak()](auto&& title) {
             if (auto tab{ weakThis.get() })
             {
                 tab->SetTabText(title);

From b092b88f043730f1b4bad532cb6800e7e154d246 Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Wed, 18 Nov 2020 10:44:34 -0500
Subject: [PATCH 09/10] addressing comments

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp | 4 +++-
 src/cascadia/TerminalApp/TabHeaderControl.h   | 6 ++----
 src/cascadia/TerminalApp/TabHeaderControl.idl | 2 +-
 src/cascadia/TerminalApp/TerminalTab.cpp      | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 8487cd046b0..4b16572ec2b 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -49,7 +49,7 @@ namespace winrt::TerminalApp::implementation
     // - Updates the zoom icon indicating whether a pane is zoomed
     // Arguments:
     // - The desired visibility state of the zoom icon
-    void TabHeaderControl::SetZoomIcon(Windows::UI::Xaml::Visibility state)
+    void TabHeaderControl::SetZoomIconVisibility(Windows::UI::Xaml::Visibility state)
     {
         HeaderZoomIcon().Visibility(state);
     }
@@ -71,6 +71,8 @@ namespace winrt::TerminalApp::implementation
 
     // Method Description:
     // - Event handler for when the rename box loses focus
+    // - When the rename box loses focus, we use the text in it as the new title
+    //   (i.e. we commit the change instead of cancelling it)
     void TabHeaderControl::RenameBoxLostFocusHandler(Windows::Foundation::IInspectable const& /*sender*/,
                                                      Windows::UI::Xaml::RoutedEventArgs const& /*e*/)
     {
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index 7ad19cb7f2d..c44df7dfbcf 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -13,7 +13,7 @@ namespace winrt::TerminalApp::implementation
     struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
     {
         TabHeaderControl();
-        void SetZoomIcon(Windows::UI::Xaml::Visibility state);
+        void SetZoomIconVisibility(Windows::UI::Xaml::Visibility state);
         void ConstructTabRenameBox();
 
         void RenameBoxLostFocusHandler(winrt::Windows::Foundation::IInspectable const& sender,
@@ -33,7 +33,5 @@ namespace winrt::TerminalApp::implementation
 
 namespace winrt::TerminalApp::factory_implementation
 {
-    struct TabHeaderControl : TabHeaderControlT<TabHeaderControl, implementation::TabHeaderControl>
-    {
-    };
+    BASIC_FACTORY(TabHeaderControl);
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index d13e9a734dc..24894313378 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -10,7 +10,7 @@ namespace TerminalApp
         String Title { get; set; };
 
         TabHeaderControl();
-        void SetZoomIcon(Windows.UI.Xaml.Visibility state);
+        void SetZoomIconVisibility(Windows.UI.Xaml.Visibility state);
         void ConstructTabRenameBox();
 
         event HeaderTitleWantsToChangeArgs HeaderTitleWantsToChange;
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index 37c327688e0..685984c74c8 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -851,7 +851,7 @@ namespace winrt::TerminalApp::implementation
         _zoomedPane = _activePane;
         _rootPane->Maximize(_zoomedPane);
         // Update the tab header to show the magnifying glass
-        _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Visible);
+        _headerControl.SetZoomIconVisibility(Windows::UI::Xaml::Visibility::Visible);
         Content(_zoomedPane->GetRootElement());
     }
     void TerminalTab::ExitZoom()
@@ -859,7 +859,7 @@ namespace winrt::TerminalApp::implementation
         _rootPane->Restore(_zoomedPane);
         _zoomedPane = nullptr;
         // Update the tab header to hide the magnifying glass
-        _headerControl.SetZoomIcon(Windows::UI::Xaml::Visibility::Collapsed);
+        _headerControl.SetZoomIconVisibility(Windows::UI::Xaml::Visibility::Collapsed);
         Content(_rootPane->GetRootElement());
     }
 

From 47ba94936728ac14708292ac449d97e1c5ff38da Mon Sep 17 00:00:00 2001
From: Pankaj Bhojwani <pabhojwa@microsoft.com>
Date: Fri, 20 Nov 2020 10:37:24 -0500
Subject: [PATCH 10/10] addressing comments

---
 src/cascadia/TerminalApp/TabHeaderControl.cpp  | 13 ++-----------
 src/cascadia/TerminalApp/TabHeaderControl.h    |  6 +++---
 src/cascadia/TerminalApp/TabHeaderControl.idl  |  8 ++++----
 src/cascadia/TerminalApp/TabHeaderControl.xaml |  3 +--
 src/cascadia/TerminalApp/TerminalTab.cpp       |  8 ++++----
 5 files changed, 14 insertions(+), 24 deletions(-)

diff --git a/src/cascadia/TerminalApp/TabHeaderControl.cpp b/src/cascadia/TerminalApp/TabHeaderControl.cpp
index 4b16572ec2b..4612ea7e481 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.cpp
+++ b/src/cascadia/TerminalApp/TabHeaderControl.cpp
@@ -45,19 +45,10 @@ namespace winrt::TerminalApp::implementation
         });
     }
 
-    // Method Description:
-    // - Updates the zoom icon indicating whether a pane is zoomed
-    // Arguments:
-    // - The desired visibility state of the zoom icon
-    void TabHeaderControl::SetZoomIconVisibility(Windows::UI::Xaml::Visibility state)
-    {
-        HeaderZoomIcon().Visibility(state);
-    }
-
     // Method Description:
     // - Show the tab rename box for the user to rename the tab title
     // - We automatically use the previous title as the initial text of the box
-    void TabHeaderControl::ConstructTabRenameBox()
+    void TabHeaderControl::BeginRename()
     {
         _receivedKeyDown = false;
 
@@ -89,6 +80,6 @@ namespace winrt::TerminalApp::implementation
         HeaderRenamerTextBox().Visibility(Windows::UI::Xaml::Visibility::Collapsed);
         HeaderTextBlock().Visibility(Windows::UI::Xaml::Visibility::Visible);
 
-        _HeaderTitleWantsToChangeHandlers(HeaderRenamerTextBox().Text());
+        _TitleChangeRequestedHandlers(HeaderRenamerTextBox().Text());
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.h b/src/cascadia/TerminalApp/TabHeaderControl.h
index c44df7dfbcf..367ce43178c 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.h
+++ b/src/cascadia/TerminalApp/TabHeaderControl.h
@@ -13,16 +13,16 @@ namespace winrt::TerminalApp::implementation
     struct TabHeaderControl : TabHeaderControlT<TabHeaderControl>
     {
         TabHeaderControl();
-        void SetZoomIconVisibility(Windows::UI::Xaml::Visibility state);
-        void ConstructTabRenameBox();
+        void BeginRename();
 
         void RenameBoxLostFocusHandler(winrt::Windows::Foundation::IInspectable const& sender,
                                        winrt::Windows::UI::Xaml::RoutedEventArgs const& e);
 
-        WINRT_CALLBACK(HeaderTitleWantsToChange, TerminalApp::HeaderTitleWantsToChangeArgs);
+        WINRT_CALLBACK(TitleChangeRequested, TerminalApp::TitleChangeRequestedArgs);
 
         WINRT_CALLBACK(PropertyChanged, Windows::UI::Xaml::Data::PropertyChangedEventHandler);
         OBSERVABLE_GETSET_PROPERTY(winrt::hstring, Title, _PropertyChangedHandlers);
+        OBSERVABLE_GETSET_PROPERTY(bool, IsPaneZoomed, _PropertyChangedHandlers);
 
     private:
         bool _receivedKeyDown{ false };
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.idl b/src/cascadia/TerminalApp/TabHeaderControl.idl
index 24894313378..a9dd3f571e0 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.idl
+++ b/src/cascadia/TerminalApp/TabHeaderControl.idl
@@ -3,16 +3,16 @@
 
 namespace TerminalApp
 {
-    delegate void HeaderTitleWantsToChangeArgs(String title);
+    delegate void TitleChangeRequestedArgs(String title);
 
     [default_interface] runtimeclass TabHeaderControl : Windows.UI.Xaml.Controls.UserControl, Windows.UI.Xaml.Data.INotifyPropertyChanged
     {
         String Title { get; set; };
+        Boolean IsPaneZoomed { get; set; };
 
         TabHeaderControl();
-        void SetZoomIconVisibility(Windows.UI.Xaml.Visibility state);
-        void ConstructTabRenameBox();
+        void BeginRename();
 
-        event HeaderTitleWantsToChangeArgs HeaderTitleWantsToChange;
+        event TitleChangeRequestedArgs TitleChangeRequested;
     }
 }
diff --git a/src/cascadia/TerminalApp/TabHeaderControl.xaml b/src/cascadia/TerminalApp/TabHeaderControl.xaml
index 1656e32111e..4c09b3b0d8e 100644
--- a/src/cascadia/TerminalApp/TabHeaderControl.xaml
+++ b/src/cascadia/TerminalApp/TabHeaderControl.xaml
@@ -5,7 +5,6 @@ the MIT License. See LICENSE in the project root for license information. -->
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:local="using:TerminalApp"
-    xmlns:mux="using:Microsoft.UI.Xaml.Controls"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d">
@@ -14,7 +13,7 @@ the MIT License. See LICENSE in the project root for license information. -->
                 Orientation="Horizontal">
         <FontIcon x:Name="HeaderZoomIcon"
                   FontFamily="Segoe MDL2 Assets"
-                  Visibility="Collapsed"
+                  Visibility="{x:Bind IsPaneZoomed, Mode=OneWay}"
                   Glyph="&#xE8A3;"
                   FontSize="12"
                   Margin="0,0,8,0"/>
diff --git a/src/cascadia/TerminalApp/TerminalTab.cpp b/src/cascadia/TerminalApp/TerminalTab.cpp
index 685984c74c8..88cb91011e4 100644
--- a/src/cascadia/TerminalApp/TerminalTab.cpp
+++ b/src/cascadia/TerminalApp/TerminalTab.cpp
@@ -39,7 +39,7 @@ namespace winrt::TerminalApp::implementation
         _CreateContextMenu();
 
         // Add an event handler for the header control to tell us when they want their title to change
-        _headerControl.HeaderTitleWantsToChange([weakThis = get_weak()](auto&& title) {
+        _headerControl.TitleChangeRequested([weakThis = get_weak()](auto&& title) {
             if (auto tab{ weakThis.get() })
             {
                 tab->SetTabText(title);
@@ -379,7 +379,7 @@ namespace winrt::TerminalApp::implementation
     // - <none>
     void TerminalTab::ActivateTabRenamer()
     {
-        _headerControl.ConstructTabRenameBox();
+        _headerControl.BeginRename();
     }
 
     // Method Description:
@@ -851,7 +851,7 @@ namespace winrt::TerminalApp::implementation
         _zoomedPane = _activePane;
         _rootPane->Maximize(_zoomedPane);
         // Update the tab header to show the magnifying glass
-        _headerControl.SetZoomIconVisibility(Windows::UI::Xaml::Visibility::Visible);
+        _headerControl.IsPaneZoomed(true);
         Content(_zoomedPane->GetRootElement());
     }
     void TerminalTab::ExitZoom()
@@ -859,7 +859,7 @@ namespace winrt::TerminalApp::implementation
         _rootPane->Restore(_zoomedPane);
         _zoomedPane = nullptr;
         // Update the tab header to hide the magnifying glass
-        _headerControl.SetZoomIconVisibility(Windows::UI::Xaml::Visibility::Collapsed);
+        _headerControl.IsPaneZoomed(false);
         Content(_rootPane->GetRootElement());
     }