Sync with vs-editor-core@d2d414ba

25 files changed, 622 insertions, 25 deletions

diff --git a/src/Editor/Text/Def/Internal/TextUI/AdornmentPositioningBehavior2.cs b/src/Editor/Text/Def/Internal/TextUI/AdornmentPositioningBehavior2.cs
new file mode 100644
index 0000000..8991855
--- /dev/null
+++ b/src/Editor/Text/Def/Internal/TextUI/AdornmentPositioningBehavior2.cs
@@ -0,0 +1,38 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// This file contain internal APIs that are subject to change without notice.
+// Use at your own risk.
+//
+namespace Microsoft.VisualStudio.Text.Editor
+{
+    /// <summary>
+    /// Defines the positioning of adornments.
+    /// </summary>
+    /// <remarks>
+    /// This enum adds a mode to the AdornmentPositioningBehavior needed for diff but we don't want to expose. 
+    /// </remarks>
+    public enum AdornmentPositioningBehavior2
+    {
+        /// <summary>
+        /// The adornment is not moved automatically.
+        /// </summary>
+        OwnerControlled = XPlatAdornmentPositioningBehavior.OwnerControlled,
+
+        /// <summary>
+        /// The adornment is positioned relative to the top left corner of the view.
+        /// </summary>
+        ViewportRelative = XPlatAdornmentPositioningBehavior.ViewportRelative,
+
+        /// <summary>
+        /// The adornment is positioned relative to the text in the view.
+        /// </summary>
+        TextRelative = XPlatAdornmentPositioningBehavior.TextRelative,
+
+        /// <summary>
+        /// Behaves like a AdornmentPositioningBehavior.TextRelative adornment but only scrolls vertically.
+        /// </summary>
+        TextRelativeVerticalOnly
+    }
+}
\ No newline at end of file
diff --git a/src/Editor/Text/Def/Internal/TextUI/IPreviewTextViewModel.cs b/src/Editor/Text/Def/Internal/TextUI/IPreviewTextViewModel.cs
new file mode 100644
index 0000000..e562367
--- /dev/null
+++ b/src/Editor/Text/Def/Internal/TextUI/IPreviewTextViewModel.cs
@@ -0,0 +1,20 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// This file contain internal APIs that are subject to change without notice.
+// Use at your own risk.
+//
+namespace Microsoft.VisualStudio.Text.Editor
+{
+    /// <summary>
+    /// <see cref="ITextViewModel"/> used by the view shown when hovering over the scroll bar (which will have the <see cref="PredefinedTextViewRoles.PreviewTextView"/> role).
+    /// </summary>
+    public interface IPreviewTextViewModel : ITextViewModel
+    {
+        /// <summary>
+        /// Pointer to the view for which this is a preview.
+        /// </summary>
+        ITextView SourceView { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextLogic/AssemblyInfo.cs b/src/Editor/Text/Def/TextLogic/AssemblyInfo.cs
index 9f96b01..5c9cc55 100644
--- a/src/Editor/Text/Def/TextLogic/AssemblyInfo.cs
+++ b/src/Editor/Text/Def/TextLogic/AssemblyInfo.cs
@@ -26,7 +26,28 @@ using System.Security.Permissions;
 
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.Commanding.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Platform.VSEditor, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Editor.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.UI.Utilities, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Language.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.TextViewUnitTestHelper, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Logic.Text.BufferUndoManager.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.EditorOptions.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.DifferenceViewer.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.Wpf.View.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.Cocoa.View.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Logic.Text.Tagging.Aggregator.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.UI.WPF.Utilities, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Language.Intellisense.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.DeferCreation.Implementation.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Logic.Text.Find.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Logic.Text.Find.Implementation.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Outlining.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.Wpf.OutliningMargin.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Editor.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Implementation.StandaloneUndo, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Logic.Text.BufferUndoManager.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Internal.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.IndentationManager.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.EditorOperations.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Find.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/BaseLeftBufferChangedEventArgs.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/BaseLeftBufferChangedEventArgs.cs
new file mode 100644
index 0000000..2a4ddc8
--- /dev/null
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/BaseLeftBufferChangedEventArgs.cs
@@ -0,0 +1,24 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    using System;
+
+    /// <summary>
+    /// Raised whenever the left buffer of an <see cref="IDifferenceBuffer2"/> changes. This can only
+    /// happen if <see cref="IDifferenceBuffer2.HasFixedBaseLeftBuffer"/> is false.
+    /// </summary>
+    public class BaseLeftBufferChangedEventArgs : EventArgs
+    {
+        public BaseLeftBufferChangedEventArgs(ITextBuffer oldBuffer, ITextBuffer newBuffer)
+        {
+            this.OldBuffer = oldBuffer;
+            this.NewBuffer = newBuffer;
+        }
+
+        public ITextBuffer OldBuffer { get; }
+        public ITextBuffer NewBuffer { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/DifferenceBufferProperties.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/DifferenceBufferProperties.cs
new file mode 100644
index 0000000..abd4b7d
--- /dev/null
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/DifferenceBufferProperties.cs
@@ -0,0 +1,20 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    public static class DifferenceBufferProperties
+    {
+        /// <summary>
+        /// Add this property to an <see cref="ITextBuffer.Properties"/> to prevent a difference buffer from computing differences when the buffer
+        /// is used as the left buffer.
+        /// </summary>
+        /// <remarks>
+        /// This is intended for situations where you want to open a difference buffer but have not, yet, loaded the baseline. You can set the
+        /// <see cref="IDifferenceBuffer.BaseLeftBuffer"/> to this and then change it to the correct buffer once it is available.
+        /// </remarks>
+        public const string PlaceholderBuffer = "PlaceholderBuffer";
+    }
+}
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer2.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer2.cs
index ebfecb6..6370508 100644
--- a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer2.cs
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer2.cs
@@ -9,22 +9,35 @@ namespace Microsoft.VisualStudio.Text.Differencing
     public interface IDifferenceBuffer2 : IDifferenceBuffer
     {
         /// <summary>
-        /// The source of the left buffer in the difference. Can be set to null.
+        /// True if the BaseLeftBuffer can never change. If false, the BaseLeftBuffer can change (via setting the InnerLeftDataModel) and
+        /// can be null.
         /// </summary>
-        new ITextBuffer BaseLeftBuffer { get; set; }
+        bool HasFixedBaseLeftBuffer { get; }
 
-        event EventHandler<BufferChangedEventArgs> BaseLeftBufferChanged;
-    }
+        /// <summary>
+        /// Raised whenever the <see cref="IDifferenceBuffer.BaseLeftBuffer"/> is changed to a different buffer.
+        /// </summary>
+        event EventHandler<BaseLeftBufferChangedEventArgs> BaseLeftBufferChanged;
 
-    public class BufferChangedEventArgs : EventArgs
-    {
-        public BufferChangedEventArgs(ITextBuffer oldBuffer, ITextBuffer newBuffer)
-        {
-            this.OldBuffer = oldBuffer;
-            this.NewBuffer = newBuffer;
-        }
+        /// <summary>
+        /// The <see cref="ITextDataModel"/> for the BaseLeftBuffer. This can be created even if <see cref="IDifferenceBuffer.BaseLeftBuffer"/> is null.
+        /// </summary>
+        ITextDataModel LeftDataModel { get; }
+
+        /// <summary>
+        /// The <see cref="ITextDataModel"/> actual ITextDataModel for the BaseLeftBuffer. This value is only meaningful if <see cref="HasFixedBaseLeftBuffer"/> is
+        /// false. Set InnerLeftDataModel to null to set the difference buffer's BaseLeftBuffer to null.
+        /// </summary>
+        ITextDataModel InnerLeftDataModel { get; set; }
 
-        public ITextBuffer OldBuffer { get; }
-        public ITextBuffer NewBuffer { get; }
+        /// <summary>
+        /// The <see cref="ITextDataModel"/> for the right buffer.
+        /// </summary>
+        ITextDataModel RightDataModel { get; }
+
+        /// <summary>
+        /// The <see cref="ITextDataModel"/> for the inline buffer. This can be created even if <see cref="IDifferenceBuffer.BaseLeftBuffer"/> is null.
+        /// </summary>
+        ITextDataModel InlineDataModel { get; }
     }
 }
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer3.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer3.cs
new file mode 100644
index 0000000..ce3ef4b
--- /dev/null
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBuffer3.cs
@@ -0,0 +1,16 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    using System;
+
+    public interface IDifferenceBuffer3 : IDifferenceBuffer2
+    {
+        /// <summary>
+        /// Raised whenever the <see cref="IDifferenceBuffer.BaseLeftBuffer"/> is about to change to a different buffer.
+        /// </summary>
+        event EventHandler<BaseLeftBufferChangedEventArgs> BaseLeftBufferChanging;
+    }
+}
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService.cs
index 5e5d61c..aaaeb26 100644
--- a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService.cs
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService.cs
@@ -19,7 +19,7 @@ namespace Microsoft.VisualStudio.Text.Differencing
         /// </summary>
         /// <param name="leftBaseBuffer">The left (old, before) buffer.</param>
         /// <param name="rightBaseBuffer">The right (new, after) buffer.</param>
-        /// <remarks>This is equivalent to calling <code>CreateDifferenceBuffer(left, right, new StringDifferenceOptions());</code>.</remarks>
+        /// <remarks>This is equivalent to calling <c>CreateDifferenceBuffer(left, right, new StringDifferenceOptions());</c>.</remarks>
         IDifferenceBuffer CreateDifferenceBuffer(ITextBuffer leftBaseBuffer, ITextBuffer rightBaseBuffer);
 
         /// <summary>
diff --git a/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService2.cs b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService2.cs
new file mode 100644
index 0000000..10cf48c
--- /dev/null
+++ b/src/Editor/Text/Def/TextLogic/DifferenceBuffer/IDifferenceBufferFactoryService2.cs
@@ -0,0 +1,59 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+using Microsoft.VisualStudio.Text.Projection;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// A factory for creating <see cref="IDifferenceBuffer"/> instances.
+    /// </summary>
+    /// <remarks>
+    /// This is a MEF service and can be imported.
+    /// </remarks>
+    public interface IDifferenceBufferFactoryService2 : IDifferenceBufferFactoryService
+    {
+        /// <summary>
+        /// Create an <see cref="IDifferenceBuffer"/> for the given left and right buffers and with the given difference options.
+        /// </summary>
+        /// <param name="leftBaseBuffer">The left (old, before) buffer.</param>
+        /// <param name="rightBaseBuffer">The right (new, after) buffer.</param>
+        /// <param name="options">The options to use in computing differences between the buffers.</param>
+        /// <param name="disableEditing">If true, disable editing in the right and inlines views.</param>
+        /// <param name="wrapLeftBuffer">If true, create a read-only projection of <paramref name="leftBaseBuffer"/> (which will prevent
+        /// that buffer from being modified through the difference buffers).</param>
+        /// <param name="wrapRightBuffer">If true and editing is disabled, create a read-only projection of <paramref name="rightBaseBuffer"/> (which will prevent
+        /// that buffer from being modified through the difference buffers).</param>
+        /// <param name="fixedBaseLeftBuffer">Allows, if false, the <see cref="IDifferenceBuffer.BaseLeftBuffer"/> can be changed.</param>
+        /// <remarks>
+        /// <para>If <paramref name="disableEditing"/> is false, then <paramref name="wrapRightBuffer"/> is ignored (and the right buffer will not be wrapped).</para>
+        /// <para>If <paramref name="wrapLeftBuffer"/> is false, then the caller of this method is responsible for making sure <paramref name="leftBaseBuffer"/> is read-only.</para>
+        /// <para>If <paramref name="disableEditing"/> is true and <paramref name="wrapRightBuffer"/> is false, then the caller of this method is responsible for making sure <paramref name="rightBaseBuffer"/> is read-only.</para>
+        /// <para>If <paramref name="fixedBaseLeftBuffer"/> is false, then <paramref name="wrapLeftBuffer"/> is ignored and <paramref name="leftBaseBuffer"/> can be null.</para>
+        /// </remarks>
+        IDifferenceBuffer2 CreateDifferenceBuffer(ITextBuffer leftBaseBuffer, ITextBuffer rightBaseBuffer, StringDifferenceOptions options,
+                                                  bool disableEditing, bool wrapLeftBuffer, bool wrapRightBuffer, bool fixedBaseLeftBuffer);
+
+        /// <summary>
+        /// Create an <see cref="IDifferenceBuffer"/> for the given left and right buffers and with the given difference options.
+        /// </summary>
+        /// <param name="innerLeftDataModel">The data model for the left buffer. This can be null.</param>
+        /// <param name="rightDataModel">The right (new, after) buffer.</param>
+        /// <param name="options">The options to use in computing differences between the buffers.</param>
+        /// <param name="disableEditing">If true, disable editing in the right and inlines views.</param>
+        /// <param name="wrapLeftBuffer">If true, create a read-only projection of <paramref name="leftBaseBuffer"/> (which will prevent
+        /// that buffer from being modified through the difference buffers).</param>
+        /// <param name="wrapRightBuffer">If true and editing is disabled, create a read-only projection of <paramref name="rightBaseBuffer"/> (which will prevent
+        /// that buffer from being modified through the difference buffers).</param>
+        /// <param name="fixedBaseLeftBuffer">Allows, if false, the <see cref="IDifferenceBuffer.BaseLeftBuffer"/> can be changed.</param>
+        /// <remarks>
+        /// <para>If <paramref name="disableEditing"/> is false, then <paramref name="wrapRightBuffer"/> is ignored (and the right buffer will not be wrapped).</para>
+        /// <para>If <paramref name="wrapLeftBuffer"/> is false, then the caller of this method is responsible for making sure <paramref name="leftBaseBuffer"/> is read-only.</para>
+        /// <para>If <paramref name="disableEditing"/> is true and <paramref name="wrapRightBuffer"/> is false, then the caller of this method is responsible for making sure <paramref name="rightBaseBuffer"/> is read-only.</para>
+        /// <para>If <paramref name="fixedBaseLeftBuffer"/> is false, then <paramref name="wrapLeftBuffer"/> is ignored and <paramref name="innerLeftDataModel"/> can be null.</para>
+        /// </remarks>
+        IDifferenceBuffer2 CreateDifferenceBuffer(ITextDataModel innerLeftDataModel, ITextDataModel rightDataModel, StringDifferenceOptions options,
+                                                  bool disableEditing, bool wrapLeftBuffer, bool wrapRightBuffer, bool fixedBaseLeftBuffer);
+    }
+}
diff --git a/src/Editor/Text/Def/TextUI/AssemblyInfo.cs b/src/Editor/Text/Def/TextUI/AssemblyInfo.cs
index e404e66..b904d55 100644
--- a/src/Editor/Text/Def/TextUI/AssemblyInfo.cs
+++ b/src/Editor/Text/Def/TextUI/AssemblyInfo.cs
@@ -16,6 +16,8 @@ using System.Security.Permissions;
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.UI.Text.Commanding.Implementation.UnitTests, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.UI.Utilities, PublicKey=" + ThisAssembly.PublicKey)]
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Platform.VSEditor, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.DifferenceViewer.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
+[assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Outlining.Implementation, PublicKey=" + ThisAssembly.PublicKey)]
 
 // InternalsVisibleTo for VS for Mac implementation assembly:
 [assembly: InternalsVisibleTo("Microsoft.VisualStudio.Text.Implementation, PublicKey=0024000004800000940000000602000000240000525341310004000001000100e57febc1f220077550a65e338d3d15d7cbd189cf4f62f7c3829dcb2f8441a6c40631d172e3deb4dc0bb7237b44ec9daeb9bd7d72c3d64c4f52b968795443cb58bc341583c29440345b8c35f72f6a31aecb2903376136f8fc35779bb422eb643f8668fa6605c697bff927e3bb10745328ff878bd1b7e42bbcb839f04baa8460bd")]
diff --git a/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerOptions.cs b/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerOptions.cs
index d4b0ba3..21ae0f9 100644
--- a/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerOptions.cs
+++ b/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerOptions.cs
@@ -35,12 +35,17 @@ namespace Microsoft.VisualStudio.Text.Differencing
         public static readonly EditorOptionKey<bool> SynchronizeSideBySideViewsId = new EditorOptionKey<bool>(DifferenceViewerOptions.SynchronizeSideBySideViewsName);
         public const string SynchronizeSideBySideViewsName = "Diff/View/SynchronizeSideBySideViews";
 
-
         /// <summary>
         /// If <c>true</c>, show the difference overview margin.
         /// </summary>
         public static readonly EditorOptionKey<bool> ShowDiffOverviewMarginId = new EditorOptionKey<bool>(DifferenceViewerOptions.ShowDiffOverviewMarginName);
         public const string ShowDiffOverviewMarginName = "Diff/View/ShowDiffOverviewMargin";
+
+        /// <summary>
+        /// If this is <c>false</c>, then the difference viewer will, even if a baseline has been specified, not show any differences.
+        /// </summary>
+        public static readonly EditorOptionKey<bool> ShowDifferencesId = new EditorOptionKey<bool>(DifferenceViewerOptions.ShowDifferencesName);
+        public const string ShowDifferencesName = "ShowDifferences";
     }
 
     /// <summary>
diff --git a/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerRoles.cs b/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerRoles.cs
index 77b7fa8..44e19c3 100644
--- a/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerRoles.cs
+++ b/src/Editor/Text/Def/TextUI/DifferenceViewer/DifferenceViewerRoles.cs
@@ -10,23 +10,43 @@ namespace Microsoft.VisualStudio.Text.Differencing
     public static class DifferenceViewerRoles
     {
         /// <summary>
-        /// The text view role for any view owned by an <see cref="IDifferenceViewer"/>.
+        /// The text view role for any view owned by an <see cref="IDifferenceViewer"/> when the underlying difference buffer will never have a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
         /// </summary>
         public const string DiffTextViewRole = "DIFF";
 
         /// <summary>
-        /// The text view role for the <see cref="IDifferenceViewer.LeftView"/>.
+        /// The text view role for the <see cref="IDifferenceViewer.LeftView"/> when the underlying difference buffer will never have a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
         /// </summary>
         public const string LeftViewTextViewRole = "LEFTDIFF";
 
         /// <summary>
-        /// The text view role for the <see cref="IDifferenceViewer.RightView"/>.
+        /// The text view role for the <see cref="IDifferenceViewer.RightView"/> when the underlying difference buffer will never have a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
         /// </summary>
         public const string RightViewTextViewRole = "RIGHTDIFF";
 
         /// <summary>
-        /// The text view role for the <see cref="IDifferenceViewer.InlineView"/>.
+        /// The text view role for the <see cref="IDifferenceViewer.InlineView"/> when the underlying difference buffer will never have a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
         /// </summary>
         public const string InlineViewTextViewRole = "INLINEDIFF";
+
+        /// <summary>
+        /// The text view role for any view owned by an <see cref="IDifferenceViewer"/> when the underlying difference buffer supports a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
+        /// </summary>
+        public const string UbiquitousDiffTextViewRole = "UBIDIFF";
+
+        /// <summary>
+        /// The text view role for the <see cref="IDifferenceViewer.LeftView"/> when the underlying difference buffer supports a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
+        /// </summary>
+        public const string UbiquitousLeftViewTextViewRole = "UBILEFTDIFF";
+
+        /// <summary>
+        /// The text view role for the <see cref="IDifferenceViewer.RightView"/> when the underlying difference buffer supports a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
+        /// </summary>
+        public const string UbiquitousRightViewTextViewRole = "UBIRIGHTDIFF";
+
+        /// <summary>
+        /// The text view role for the <see cref="IDifferenceViewer.InlineView"/> when the underlying difference buffer supports a null <see cref="IDifferenceBuffer.BaseLeftBuffer"/>.
+        /// </summary>
+        public const string UbiquitousInlineViewTextViewRole = "UBIINLINEDIFF";
     }
 }
diff --git a/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer2.cs b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer2.cs
index 3b9a4a8..e1e1055 100644
--- a/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer2.cs
+++ b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer2.cs
@@ -9,8 +9,27 @@ namespace Microsoft.VisualStudio.Text.Differencing
     public interface IDifferenceViewer2 : IDifferenceViewer
     {
         /// <summary>
-        /// Raised when the difference viewer is fully initialized.
+        /// Does the right view exist?
         /// </summary>
-        event EventHandler Initialized;
+        /// <remarks>
+        /// Differences views are created lazily <see cref="IDifferenceViewer.RightView"/> will create the view if it does not already exist.
+        /// </remarks>
+        bool RightViewExists { get; }
+
+        /// <summary>
+        /// Does the left view exist?
+        /// </summary>
+        /// <remarks>
+        /// Differences views are created lazily <see cref="IDifferenceViewer.LeftView"/> will create the view if it does not already exist.
+        /// </remarks>
+        bool LeftViewExists { get; }
+
+        /// <summary>
+        /// Does the Inline view exist?
+        /// </summary>
+        /// <remarks>
+        /// Differences views are created lazily <see cref="IDifferenceViewer.InlineView"/> will create the view if it does not already exist.
+        /// </remarks>
+        bool InlineViewExists { get; }
     }
 }
diff --git a/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer3.cs b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer3.cs
new file mode 100644
index 0000000..517a5b0
--- /dev/null
+++ b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewer3.cs
@@ -0,0 +1,20 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    using System;
+
+    public interface IDifferenceViewer3 : IDifferenceViewer2
+    {
+        /// <summary>
+        /// Should the differences be displayed?
+        /// </summary>
+        /// <remarks>
+        /// <para>This will be true if and only if there is a baseline and if the <see cref="DifferenceViewerOptions.ShowDifferencesId"/> option is true.</para>
+        /// <para><see cref="IDifferenceViewer.ViewModeChanged"/> will be raised whenever this value changes.</para>
+        /// </remarks>
+        bool DisplayDifferences { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewerTextViewModel.cs b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewerTextViewModel.cs
new file mode 100644
index 0000000..fa5a33a
--- /dev/null
+++ b/src/Editor/Text/Def/TextUI/DifferenceViewer/IDifferenceViewerTextViewModel.cs
@@ -0,0 +1,49 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// A <see cref="ITextViewModel"/> used by <see cref="IDifferenceViewer"/>.
+    /// </summary>
+    internal interface IDifferenceViewerTextViewModel
+    {
+        /// <summary>
+        /// The view type for a view created by an <see cref="IDifferenceViewer"/>.
+        /// </summary>
+        DifferenceViewType ViewType { get; }
+
+        /// <summary>
+        /// The currently-used snapshot difference that matches up with the current snapshot
+        /// of the inline buffer.
+        /// </summary>
+        /// <remarks>Will be <c>null</c> before the first snapshot difference is computed.</remarks>
+        ISnapshotDifference CurrentSnapshotDifference { get; }
+
+        /// <summary>
+        /// Are the left and right views are synchronized in the side by side view.
+        /// </summary>
+        /// <remarks>
+        /// <para>In the side by side view, the left and right views are, normally, synchronized so that so that matching text always shown in each view.
+        /// If this synchronization is turned off, then each view will scroll independently.</para>
+        /// </remarks>
+        bool AreViewsSynchronized { get; }
+
+        /// <summary>
+        /// The view for displaying the left buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when view mode
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        ITextView LeftView { get; }
+
+        /// <summary>
+        /// The view for displaying the right buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when view mode
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        ITextView RightView { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextUI/Editor/ITextView3.cs b/src/Editor/Text/Def/TextUI/Editor/ITextView3.cs
index b4a6a0f..f7b5b64 100644
--- a/src/Editor/Text/Def/TextUI/Editor/ITextView3.cs
+++ b/src/Editor/Text/Def/TextUI/Editor/ITextView3.cs
@@ -24,5 +24,7 @@ namespace Microsoft.VisualStudio.Text.Editor
 
         bool IsKeyboardFocused { get; }
         event EventHandler IsKeyboardFocusedChanged;
+
+        IViewSynchronizationManager SynchronizationManager { get; set; }
     }
 }
\ No newline at end of file
diff --git a/src/Editor/Text/Def/Internal/TextUIWpf/IViewSynchronizationManager.cs b/src/Editor/Text/Def/TextUI/Editor/IViewSynchronizationManager.cs
index 70eddaa..70eddaa 100644
--- a/src/Editor/Text/Def/Internal/TextUIWpf/IViewSynchronizationManager.cs
+++ b/src/Editor/Text/Def/TextUI/Editor/IViewSynchronizationManager.cs
diff --git a/src/Editor/Text/Def/TextUI/EditorOptions/InternalOptions.cs b/src/Editor/Text/Def/TextUI/EditorOptions/InternalOptions.cs
new file mode 100644
index 0000000..3c23800
--- /dev/null
+++ b/src/Editor/Text/Def/TextUI/EditorOptions/InternalOptions.cs
@@ -0,0 +1,30 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+// This file contain internal APIs that are subject to change without notice.
+// Use at your own risk.
+//
+namespace Microsoft.VisualStudio.Text.Editor
+{
+    /// <summary>
+    /// Various editor options that we shouldn't be made public.
+    /// </remarks>
+    internal static class InternalOptions
+    {
+        public const string SuppressOutliningOptionName = "SuppressOutlining";
+        public readonly static EditorOptionKey<bool> SuppressOutliningOptionId = new EditorOptionKey<bool>(SuppressOutliningOptionName);
+
+        /// <summary>
+        /// The option definition that determines the vertical scroll sensitivity in Editor.
+        /// </summary>
+        internal static readonly EditorOptionKey<int> EditorVerticalScrollSensitivityId = new EditorOptionKey<int>(EditorVerticalScrollSensitivityName);
+        internal const string EditorVerticalScrollSensitivityName = "EditorVerticalScrollSensitivity";
+
+        /// <summary>
+        /// The option definition that determines the horizontal scroll sensitivity in Editor.
+        /// </summary>
+        internal static readonly EditorOptionKey<int> EditorHorizontalScrollSensitivityId = new EditorOptionKey<int>(EditorHorizontalScrollSensitivityName);
+        internal const string EditorHorizontalScrollSensitivityName = "EditorHorizontalScrollSensitivity";
+    }
+}
diff --git a/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/CreateTextViewHostCallback.cs b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/CreateTextViewHostCallback.cs
new file mode 100644
index 0000000..8afd865
--- /dev/null
+++ b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/CreateTextViewHostCallback.cs
@@ -0,0 +1,30 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+using System.Windows;
+using AppKit;
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// Callback used with <see cref="ICocoaDifferenceViewerFactoryService"/> to create a text view host.
+    /// </summary>
+    /// <param name="textViewModel">The text view model to use in creating the text view.</param>
+    /// <param name="roles">The roles specific to this view.</param>
+    /// <param name="options">The options to use in creating the text view.</param>
+    /// <param name="visualElement">The top-level visual element for this host.</param>
+    /// <param name="textViewHost">The created text view host.</param>
+    /// <remarks>
+    /// <para>
+    /// To get standard text view roles, the implementation of this method should concatenate the given <paramref name="roles"/> with
+    /// <see cref="ITextEditorFactoryService.DefaultRoles"/>.
+    /// </para>
+    /// <para>
+    /// In most cases, the visual element can just be the <paramref name="textViewHost"/>'s <see cref="ICocoaTextViewHost.HostControl"/>.
+    /// </para>
+    /// </remarks>
+    public delegate void CreateTextViewHostCallback(IDifferenceTextViewModel textViewModel, ITextViewRoleSet roles, IEditorOptions options,
+                                                    out NSView visualElement, out ICocoaTextViewHost textViewHost);
+}
diff --git a/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewer.cs b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewer.cs
new file mode 100644
index 0000000..cb5dd97
--- /dev/null
+++ b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewer.cs
@@ -0,0 +1,84 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+using System.Windows;
+using AppKit;
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// A Cocoa-specific version of an <see cref="IDifferenceViewer"/>, which provides access to the
+    /// <see cref="VisualElement" /> used to host the viewer and the various text view hosts as <see cref="ICocoaTextViewHost" />.
+    /// </summary>
+    public interface ICocoaDifferenceViewer : IDifferenceViewer
+    {
+        /// <summary>
+        /// Initialize the DifferenceViewer, hooking it to the specified buffer and using the callback to create the text view hosts.
+        /// </summary>
+        /// <param name="differenceBuffer"></param>
+        /// <param name="createTextViewHost"></param>
+        /// <param name="parentOptions"></param>
+        /// <remarks>
+        /// <para>This method should only be called if the CreateUninitializedDifferenceView method on the <see cref="ICocoaDifferenceViewerFactoryService"/> is used. Otherwise, it is
+        /// called by the factory.</para>
+        /// <para>The viewer does not have to be initialized immediately. You can wait until the Loaded event on the VisualElement.</para>
+        /// </remarks>
+        void Initialize(IDifferenceBuffer differenceBuffer,
+                        CreateTextViewHostCallback createTextViewHost,
+                        IEditorOptions parentOptions = null);
+
+        /// <summary>
+        /// Has this viewer been initialized?
+        /// </summary>
+        bool IsInitialized { get; }
+
+        /// <summary>
+        /// The view for displaying <see cref="DifferenceViewMode.Inline"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.Inline"/>.</remarks>
+        new ICocoaTextView InlineView { get; }
+
+        /// <summary>
+        /// The view for displaying the left buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        new ICocoaTextView LeftView { get; }
+
+        /// <summary>
+        /// The view for displaying the right buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        new ICocoaTextView RightView { get; }
+
+        /// <summary>
+        /// The host for displaying <see cref="DifferenceViewMode.Inline"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.Inline"/>.</remarks>
+        ICocoaTextViewHost InlineHost { get; }
+
+        /// <summary>
+        /// The host for displaying the left buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        ICocoaTextViewHost LeftHost { get; }
+
+        /// <summary>
+        /// The host for displaying the right buffer for <see cref="DifferenceViewMode.SideBySide"/> differences.
+        /// </summary>
+        /// <remarks>Will never be <c>null</c>, but will only be visible when <see cref="IDifferenceViewer.ViewMode"/>
+        /// is set to <see cref="DifferenceViewMode.SideBySide"/>.</remarks>
+        ICocoaTextViewHost RightHost { get; }
+
+        /// <summary>
+        /// The visual element of this viewer.
+        /// </summary>
+        NSView VisualElement { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewerFactoryService.cs b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewerFactoryService.cs
new file mode 100644
index 0000000..2fda646
--- /dev/null
+++ b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/ICocoaDifferenceViewerFactoryService.cs
@@ -0,0 +1,60 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// A service for creating <see cref="ICocoaDifferenceViewer"/>s.
+    /// </summary>
+    /// <remarks>
+    /// This is a MEF service to be imported.
+    /// </remarks>
+    public interface ICocoaDifferenceViewerFactoryService
+    {
+        /// <summary>
+        /// Create an <see cref="IDifferenceViewer"/> over the given <see cref="IDifferenceBuffer"/>.
+        /// </summary>
+        /// <param name="buffer">The difference buffer to display.</param>
+        /// <param name="parentOptions">The parent of the editor options for the difference viewer (if null, the global options are the parent).</param>
+        /// <returns>A difference viewer.</returns>
+        ICocoaDifferenceViewer CreateDifferenceView(IDifferenceBuffer buffer, IEditorOptions parentOptions = null);
+
+        /// <summary>
+        /// Create an <see cref="IDifferenceViewer"/> over the given <see cref="IDifferenceBuffer"/> with the given set of roles.
+        /// </summary>
+        /// <param name="buffer">The difference buffer to display.</param>
+        /// <param name="roles">The text view roles to use for the created views.</param>
+        /// <param name="parentOptions">The parent of the editor options for the difference viewer (if null, the global options are the parent).</param>
+        /// <returns>A difference viewer.</returns>
+        ICocoaDifferenceViewer CreateDifferenceView(IDifferenceBuffer buffer, ITextViewRoleSet roles, IEditorOptions parentOptions = null);
+
+        /// <summary>
+        /// Create an <see cref="IDifferenceViewer"/> over the given <see cref="IDifferenceBuffer"/>, using the given
+        /// callback to create the individual views (inline, left, and right).
+        /// </summary>
+        /// <param name="buffer">The difference buffer to display.</param>
+        /// <param name="callback">The callback to use to create individual views.</param>
+        /// <param name="parentOptions">The parent of the editor options for the difference viewer (if null, the global options are the parent).</param>
+        /// <returns>A difference viewer.</returns>
+        ICocoaDifferenceViewer CreateDifferenceView(IDifferenceBuffer buffer, CreateTextViewHostCallback callback, IEditorOptions parentOptions = null);
+
+        /// <summary>
+        /// Create an <see cref="IDifferenceViewer"/> over the given <see cref="IDifferenceBuffer"/>, without initializing it.
+        /// </summary>
+        /// <returns>A difference viewer.</returns>
+        /// <remarks>
+        /// The only legitimate property call on an uninitialized viwer is the VisualElement property.
+        /// </remarks>
+        ICocoaDifferenceViewer CreateUninitializedDifferenceView();
+
+        /// <summary>
+        /// If the given text view is owned by a difference viewer, retrieve that difference viewer.
+        /// </summary>
+        /// <param name="textView">The view to find the difference viewer for.</param>
+        /// <returns>A difference viewer, if one exists.  Otherwise, <c>null</c>.</returns>
+        ICocoaDifferenceViewer TryGetViewerForTextView(ITextView textView);
+    }
+}
diff --git a/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModel.cs b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModel.cs
new file mode 100644
index 0000000..e8a788f
--- /dev/null
+++ b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModel.cs
@@ -0,0 +1,25 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    using Microsoft.VisualStudio.Text.Editor;
+
+    /// <summary>
+    /// Represents a set of zero or more <see cref="ITextBuffer"/> objects that are unique to the presentation of text
+    /// in a particular <see cref="ITextView"/>.
+    /// </summary>
+    public interface IDifferenceTextViewModel : ITextViewModel
+    {
+        /// <summary>
+        /// A pointer to the difference viewer that created the view that uses this IDifferenceTextViewModel.
+        /// </summary>
+        ICocoaDifferenceViewer Viewer { get; }
+
+        /// <summary>
+        /// The type of the view that uses this IDifferenceTextViewModel.
+        /// </summary>
+        DifferenceViewType ViewType { get; }
+    }
+}
diff --git a/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModelProvider.cs b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModelProvider.cs
new file mode 100644
index 0000000..cce4075
--- /dev/null
+++ b/src/Editor/Text/Def/TextUICocoa/DifferenceViewer/IDifferenceTextViewModelProvider.cs
@@ -0,0 +1,30 @@
+//
+//  Copyright (c) Microsoft Corporation. All rights reserved.
+//  Licensed under the MIT License. See License.txt in the project root for license information.
+//
+
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.VisualStudio.Text.Differencing
+{
+    /// <summary>
+    /// Provides <see cref="ITextViewModel"/> objects.
+    /// </summary>
+    /// <remarks>This is a MEF component part, and should be exported with the following attribute:
+    /// [Export(NameSource=typeof(ITextViewModelProvider))]
+    /// Component exporters must specify at least one ContentTypeAttribute characterizing the data
+    /// models to which they apply.
+    /// </remarks>
+    public interface IDifferenceTextViewModelProvider
+    {
+        /// <summary>
+        /// Creates an <see cref="ITextViewModel"/> for the given <see cref="ITextDataModel"/>.
+        /// </summary>
+        /// <param name="viewer">The <see cref="ICocoaDifferenceViewer"/> in which the views are being created.</param>
+        /// <param name="viewType">The <see cref="DifferenceViewType"/> of the view being created.</param>
+        /// <param name="dataModel">The <see cref="ITextDataModel"/> for which to create the <see cref="ITextViewModel"/>.</param>
+        /// <returns>The <see cref="ITextViewModel"/> created for <paramref name="dataModel"/>, 
+        /// or <c>null</c> if the text view model cannot be created.</returns>
+        IDifferenceTextViewModel CreateTextViewModel(ICocoaDifferenceViewer viewer, DifferenceViewType viewType, ITextDataModel dataModel);
+    }
+}
diff --git a/src/Editor/Text/Impl/Outlining/OutliningManagerService.cs b/src/Editor/Text/Impl/Outlining/OutliningManagerService.cs
index 081672e..57e5dd5 100644
--- a/src/Editor/Text/Impl/Outlining/OutliningManagerService.cs
+++ b/src/Editor/Text/Impl/Outlining/OutliningManagerService.cs
@@ -12,6 +12,7 @@ namespace Microsoft.VisualStudio.Text.Outlining
     using Microsoft.VisualStudio.Text.Editor;
     using Microsoft.VisualStudio.Text.Tagging;
     using Microsoft.VisualStudio.Threading;
+    using Microsoft.VisualStudio.Utilities;
     using Microsoft.Win32;
 
     [Export(typeof(IOutliningManagerService))]
@@ -41,5 +42,14 @@ namespace Microsoft.VisualStudio.Text.Outlining
                 return manager;
             });
         }
+
+        [Export(typeof(EditorOptionDefinition))]
+        [Name(InternalOptions.SuppressOutliningOptionName)]
+        internal sealed class SuppressOutliningOption : EditorOptionDefinition<bool>
+        {
+            public override bool Default => false;
+
+            public override EditorOptionKey<bool> Key => InternalOptions.SuppressOutliningOptionId;
+        }
     }
 }
diff --git a/src/FPF/WindowsBase/System.Windows.Threading/DispatcherOperation.cs b/src/FPF/WindowsBase/System.Windows.Threading/DispatcherOperation.cs
index 4fd9847..256ccb8 100644
--- a/src/FPF/WindowsBase/System.Windows.Threading/DispatcherOperation.cs
+++ b/src/FPF/WindowsBase/System.Windows.Threading/DispatcherOperation.cs
@@ -7,6 +7,7 @@ using System.Threading;
 using System.Threading.Tasks;
 
 using CoreFoundation;
+using Foundation;
 
 namespace System.Windows.Threading
 {
@@ -56,7 +57,7 @@ namespace System.Windows.Threading
 
         internal DispatcherOperation BeginInvoke()
         {
-            DispatchQueue.MainQueue.DispatchAsync(() =>
+            NSRunLoop.Main.BeginInvokeOnMainThread(() =>
             {
                 CoreInvoke(beginInvokeBehavior: true);
                 if (exception != null)
@@ -71,7 +72,7 @@ namespace System.Windows.Threading
             if (taskSource == null)
                 throw new InvalidOperationException();
 
-            DispatchQueue.MainQueue.DispatchAsync(() =>
+            NSRunLoop.Main.BeginInvokeOnMainThread(() =>
             {
                 try
                 {
@@ -102,8 +103,7 @@ namespace System.Windows.Threading
             var mainQueue = DispatchQueue.MainQueue;
 
             if (DispatchQueue.CurrentQueue != mainQueue)
-                mainQueue.DispatchSync(
-                    () => CoreInvoke(beginInvokeBehavior: false));
+                NSRunLoop.Main.InvokeOnMainThread(() => CoreInvoke(beginInvokeBehavior: false));
             else
                 CoreInvoke(beginInvokeBehavior: false);