Set working folder for the solution added.

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioProjectFactory.cs

@@ -7,6 +7,7 @@
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.VisualStudio.LanguageServices.Implementation.TaskList;
+using Microsoft.VisualStudio.LanguageServices.Storage;
 using Microsoft.VisualStudio.Shell.Interop;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem
@@ -84,6 +85,10 @@ public VisualStudioProject CreateAndAddToWorkspace(string projectUniqueName, str
                             VersionStamp.Create(),
                             solutionPathToSetWithOnSolutionAdded,
                             projects: new[] { projectInfo }));
+
+                    // set working folder for the persistent service
+                    var persistenceService = w.Services.GetRequiredService<IPersistentStorageLocationService>() as VisualStudioPersistentStorageLocationService;
+                    persistenceService?.UpdateForVisualStudioWorkspace(w);
                 }
                 else
                 {

src/VisualStudio/IntegrationTest/IntegrationTests/CSharp/CSharpFindReferences.cs

@@ -150,5 +150,14 @@ static void Main()
                     }
                 });
         }
+
+        [WpfFact, Trait(Traits.Feature, Traits.Features.FindReferences)]
+        public void VerifyWorkingFolder()
+        {
+            SetUpEditor(@"class EmptyContent {$$}");
+
+            // verify working folder has set
+            Assert.NotNull(VisualStudio.Workspace.GetWorkingFolder());
+        }
     }
 }

src/VisualStudio/IntegrationTest/TestUtilities/InProcess/VisualStudioWorkspace_InProc.cs

@@ -7,6 +7,7 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Editor.Options;
 using Microsoft.CodeAnalysis.Editor.Shared.Options;
+using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.CodeAnalysis.Shared.TestHooks;
 using Microsoft.VisualStudio.LanguageServices;
@@ -171,5 +172,11 @@ public void SetFeatureOption(string feature, string optionName, string language,
 
                 optionService.SetOptions(optionService.GetOptions().WithChangedOption(optionKey, value));
             });
+
+        public string GetWorkingFolder()
+        {
+            var service = _visualStudioWorkspace.Services.GetRequiredService<IPersistentStorageLocationService>();
+            return service.TryGetStorageLocation(_visualStudioWorkspace.CurrentSolution.Id);
+        }
     }
 }

src/VisualStudio/IntegrationTest/TestUtilities/OutOfProcess/VisualStudioWorkspace_OutOfProc.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Shared.TestHooks;
@@ -78,5 +79,7 @@ public void SetFullSolutionAnalysis(bool value)
 
         public void SetFeatureOption(string feature, string optionName, string language, string valueString)
             => _inProc.SetFeatureOption(feature, optionName, language, valueString);
+
+        public string GetWorkingFolder() => _inProc.GetWorkingFolder();
     }
 }