diff --git a/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs b/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
index 793d9e0a8be3283ee479a7ef39927b591fd14f87..7ade00250b7c41ff6bdef79d783e91b8896b7d14 100644
--- a/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
+++ b/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
@@ -10,7 +10,7 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.CodeActions.MoveType
 {
     public partial class MoveTypeTests : CSharpMoveTypeTestsBase
     {
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestMissing_OnMatchingFileName()
         {
             var code =
@@ -19,7 +19,7 @@ public async Task TestMissing_OnMatchingFileName()
             await TestMissingInRegularAndScriptAsync(code);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestMissing_Nested_OnMatchingFileName_Simple()
         {
             var code =
@@ -31,7 +31,7 @@ public async Task TestMissing_Nested_OnMatchingFileName_Simple()
             await TestMissingInRegularAndScriptAsync(code);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestMatchingFileName_CaseSensitive()
         {
             var code =
@@ -40,7 +40,7 @@ public async Task TestMatchingFileName_CaseSensitive()
             await TestActionCountAsync(code, count: 2);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestForSpans1()
         {
             var code =
@@ -50,7 +50,7 @@ class Class2 { }";
             await TestMissingInRegularAndScriptAsync(code);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestForSpans2()
         {
             var code =
@@ -64,7 +64,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         [WorkItem(14008, "https://github.com/dotnet/roslyn/issues/14008")]
         public async Task TestMoveToNewFileWithFolders()
         {
@@ -88,7 +88,7 @@ class Class2 { }
                 destinationDocumentText, destinationDocumentContainers: ImmutableArray.Create("A", "B"));
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestForSpans3()
         {
             var code =
@@ -98,7 +98,7 @@ class Class2 { }";
             await TestMissingInRegularAndScriptAsync(code);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestForSpans4()
         {
             var code =
@@ -112,7 +112,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithNoContainerNamespace()
         {
             var code =
@@ -126,7 +126,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithWithUsingsAndNoContainerNamespace()
         {
             var code =
@@ -149,7 +149,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithWithMembers()
         {
             var code =
@@ -185,7 +185,7 @@ void Print(int x)
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithWithMembers2()
         {
             var code =
@@ -235,7 +235,7 @@ void Print(int x)
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveAnInterface()
         {
             var code =
@@ -249,7 +249,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveAStruct()
         {
             var code =
@@ -263,7 +263,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveAnEnum()
         {
             var code =
@@ -277,7 +277,7 @@ class Class2 { }";
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithWithContainerNamespace()
         {
             var code =
@@ -303,7 +303,7 @@ class Class1 { }
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypeToNewFile_Simple()
         {
             var code =
@@ -340,7 +340,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypePreserveModifiers()
         {
             var code =
@@ -377,7 +377,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         [WorkItem(14004, "https://github.com/dotnet/roslyn/issues/14004")]
         public async Task MoveNestedTypeToNewFile_Attributes1()
         {
@@ -419,7 +419,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         [WorkItem(14484, "https://github.com/dotnet/roslyn/issues/14484")]
         public async Task MoveNestedTypeToNewFile_Comments1()
         {
@@ -463,7 +463,7 @@ class Class2
                 ignoreTrivia: false);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypeToNewFile_Simple_DottedName()
         {
             var code =
@@ -500,7 +500,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText, index: 1);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypeToNewFile_ParentHasOtherMembers()
         {
             var code =
@@ -543,7 +543,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypeToNewFile_HasOtherTopLevelMembers()
         {
             var code =
@@ -595,7 +595,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveNestedTypeToNewFile_HasMembers()
         {
             var code =
@@ -643,7 +643,7 @@ class Class2
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         [WorkItem(13969, "https://github.com/dotnet/roslyn/issues/13969")]
         public async Task MoveTypeInFileWithComplexHierarchy()
         {
@@ -755,7 +755,7 @@ class InnerClass3
             await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText);
         }
 
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeUsings1()
         {
             var code =
@@ -794,7 +794,7 @@ class Inner {
         }
 
         [WorkItem(16283, "https://github.com/dotnet/roslyn/issues/16283")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestLeadingTrivia1()
         {
             var code =
@@ -832,7 +832,7 @@ class Inner2
         }
 
         [WorkItem(17171, "https://github.com/dotnet/roslyn/issues/17171")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestInsertFinalNewLine()
         {
             var code =
@@ -875,7 +875,7 @@ class Inner2
         }
 
         [WorkItem(17171, "https://github.com/dotnet/roslyn/issues/17171")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task TestInsertFinalNewLine2()
         {
             var code =
@@ -917,7 +917,7 @@ class Inner2
         }
 
         [WorkItem(16282, "https://github.com/dotnet/roslyn/issues/16282")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeRemoveOuterInheritanceTypes()
         {
             var code =
@@ -946,7 +946,7 @@ class Inner : IWhatever {
         }
 
         [WorkItem(17930, "https://github.com/dotnet/roslyn/issues/17930")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithDirectives1()
         {
             var code =
@@ -998,7 +998,7 @@ public class Inner
         }
 
         [WorkItem(17930, "https://github.com/dotnet/roslyn/issues/17930")]
-        [WpfFact(Skip = "https://github.com/dotnet/roslyn/issues/18766"), Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
         public async Task MoveTypeWithDirectives2()
         {
             var code =
diff --git a/src/EditorFeatures/CSharpTest/CodeActions/Preview/PreviewExceptionTests.cs b/src/EditorFeatures/CSharpTest/CodeActions/Preview/PreviewExceptionTests.cs
index 7a1e808ed70331cd49d0efec913668b37749fd72..9bdde4acbb6ce38de5b9db6ebe56ee5917939c05 100644
--- a/src/EditorFeatures/CSharpTest/CodeActions/Preview/PreviewExceptionTests.cs
+++ b/src/EditorFeatures/CSharpTest/CodeActions/Preview/PreviewExceptionTests.cs
@@ -10,10 +10,9 @@
 using Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces;
 using Microsoft.CodeAnalysis.Extensions;
 using Microsoft.CodeAnalysis.Text;
-using Roslyn.Utilities;
 using Roslyn.Test.Utilities;
+using Roslyn.Utilities;
 using Xunit;
-using Microsoft.CodeAnalysis.Editor.UnitTests.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.CodeRefactorings
 {
@@ -28,7 +27,7 @@ public async Task TestExceptionInComputePreview()
             }
         }
 
-        [Fact]
+        [WpfFact]
         public void TestExceptionInDisplayText()
         {
             using (var workspace = CreateWorkspaceFromFile("class D {}", new TestParameters()))
@@ -83,8 +82,8 @@ private async Task ActionSets(TestWorkspace workspace, CodeRefactoringProvider p
         }
 
         private static void RefactoringSetup(
-            TestWorkspace workspace, CodeRefactoringProvider provider, List<CodeAction> codeActions, 
-            out EditorLayerExtensionManager.ExtensionManager extensionManager, 
+            TestWorkspace workspace, CodeRefactoringProvider provider, List<CodeAction> codeActions,
+            out EditorLayerExtensionManager.ExtensionManager extensionManager,
             out VisualStudio.Text.ITextBuffer textBuffer)
         {
             var document = GetDocument(workspace);
@@ -96,4 +95,4 @@ private async Task ActionSets(TestWorkspace workspace, CodeRefactoringProvider p
             textBuffer = document.GetTextAsync().Result.Container.GetTextBuffer();
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/EditorFeatures/Core/Implementation/Preview/PreviewFactoryService.cs b/src/EditorFeatures/Core/Implementation/Preview/PreviewFactoryService.cs
index deca042b4a72f5af188b5b3b5a24b273605b369f..effef18fd55eafd64deb291cc356565ce455895c 100644
--- a/src/EditorFeatures/Core/Implementation/Preview/PreviewFactoryService.cs
+++ b/src/EditorFeatures/Core/Implementation/Preview/PreviewFactoryService.cs
@@ -14,6 +14,7 @@
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
 using Microsoft.CodeAnalysis.Text.Shared.Extensions;
+using Microsoft.CodeAnalysis.Utilities;
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Differencing;
 using Microsoft.VisualStudio.Text.Editor;
@@ -48,6 +49,8 @@ internal class PreviewFactoryService : ForegroundThreadAffinitizedObject, IPrevi
             IDifferenceBufferFactoryService differenceBufferService,
             IWpfDifferenceViewerFactoryService differenceViewerService)
         {
+            Contract.ThrowIfTrue(this.ForegroundKind == ForegroundThreadDataKind.Unknown);
+
             _textBufferFactoryService = textBufferFactoryService;
             _contentTypeRegistryService = contentTypeRegistryService;
             _projectionBufferFactoryService = projectionBufferFactoryService;
diff --git a/src/EditorFeatures/Core/Shared/Utilities/ForegroundThreadAffinitizedObject.cs b/src/EditorFeatures/Core/Shared/Utilities/ForegroundThreadAffinitizedObject.cs
index 4ee78bf1bd32371aebe4c8e209bb190a8e142702..3ea2795f0f80dedb8cde3ac917bd6d9181d29346 100644
--- a/src/EditorFeatures/Core/Shared/Utilities/ForegroundThreadAffinitizedObject.cs
+++ b/src/EditorFeatures/Core/Shared/Utilities/ForegroundThreadAffinitizedObject.cs
@@ -70,6 +70,8 @@ internal static ForegroundThreadData CurrentForegroundThreadData
 
         internal TaskScheduler ForegroundTaskScheduler => _foregroundThreadDataWhenCreated.TaskScheduler;
 
+        internal ForegroundThreadDataKind ForegroundKind => _foregroundThreadDataWhenCreated.Kind;
+
         // HACK: This is a dangerous way of establishing the 'foreground' thread affinity of an 
         // AppDomain.  This method should be deleted in favor of forcing derivations of this type
         // to either explicitly inherit WPF Dispatcher thread or provide an explicit thread