diff --git a/src/Protocol/DelegatingHandlers.cs b/src/Protocol/DelegatingHandlers.cs
index fd0b8d8d5..3afd72cbe 100644
--- a/src/Protocol/DelegatingHandlers.cs
+++ b/src/Protocol/DelegatingHandlers.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
@@ -377,7 +377,7 @@ async Task<TResponse> IRequestHandler<TItem, TResponse>.Handle(TItem request,
                 CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<TItem>.Noop)
                 {
                     _handler(request, observer, _capability, cancellationToken);
                     await observer;
@@ -435,7 +435,7 @@ public PartialResult(Guid id, Action<TItem, IObserver<TItem>, CancellationToken>
             async Task<TResponse> IRequestHandler<TItem, TResponse>.Handle(TItem request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<TItem>.Noop)
                 {
                     _handler(request, observer, cancellationToken);
                     await observer;
@@ -491,7 +491,7 @@ public PartialResultCapability(Guid id, Action<TItem, TCapability, IObserver<TIt
             async Task<TResponse> IRequestHandler<TItem, TResponse>.Handle(TItem request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<TItem>.Noop)
                 {
                     _handler(request, _capability, observer, cancellationToken);
                     await observer;
@@ -547,7 +547,7 @@ public PartialResult(Guid id, Action<TItem, IObserver<TItem>, CancellationToken>
             async Task<TResponse> IRequestHandler<TItem, TResponse>.Handle(TItem request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<TItem>.Noop)
                 {
                     _handler(request, observer, cancellationToken);
                     await observer;
@@ -604,7 +604,7 @@ public PartialResults(Guid id, Action<TParams, IObserver<IEnumerable<TItem>>, TC
             async Task<TResponse> IRequestHandler<TParams, TResponse>.Handle(TParams request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<IEnumerable<TItem>>.Noop)
                 {
                     _handler(request, observer, _capability, cancellationToken);
                     await observer;
@@ -668,7 +668,7 @@ public PartialResults(Guid id, Action<TParams, IObserver<IEnumerable<TItem>>, Ca
             async Task<TResponse> IRequestHandler<TParams, TResponse>.Handle(TParams request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<IEnumerable<TItem>>.Noop)
                 {
                     _handler(request, observer, cancellationToken);
                     await observer;
@@ -729,7 +729,7 @@ public PartialResultsCapability(Guid id, Action<TParams, TCapability, IObserver<
             async Task<TResponse> IRequestHandler<TParams, TResponse>.Handle(TParams request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<IEnumerable<TItem>>.Noop)
                 {
                     _handler(request, _capability, observer, cancellationToken);
                     await observer;
@@ -791,7 +791,7 @@ public PartialResults(Guid id, Action<TParams, IObserver<IEnumerable<TItem>>, Ca
             async Task<TResponse> IRequestHandler<TParams, TResponse>.Handle(TParams request, CancellationToken cancellationToken)
             {
                 var observer = _progressManager.For(request, cancellationToken);
-                if (observer != null)
+                if (observer != ProgressObserver<IEnumerable<TItem>>.Noop)
                 {
                     _handler(request, observer, cancellationToken);
                     await observer;
diff --git a/test/Lsp.Tests/Integration/PartialItemTests.cs b/test/Lsp.Tests/Integration/PartialItemTests.cs
index c785561dc..e15c4d252 100644
--- a/test/Lsp.Tests/Integration/PartialItemTests.cs
+++ b/test/Lsp.Tests/Integration/PartialItemTests.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reactive;
@@ -56,6 +56,19 @@ await client.TextDocument.RequestCodeLens(new CodeLensParams() {
             items.Select(z => z.Command.Name).Should().ContainInOrder("CodeLens 1", "CodeLens 2", "CodeLens 3");
         }
 
+        [Fact]
+        public async Task Should_Behave_Like_An_Observable_Without_Progress_Support()
+        {
+            var (client, server) = await Initialize(ConfigureClient, ConfigureServerWithDelegateCodeLens);
+
+            var response = await client.SendRequest(new CodeLensParams() {
+                TextDocument = new TextDocumentIdentifier(@"c:\test.cs")
+            }, CancellationToken);
+
+            response.Should().HaveCount(3);
+            response.Select(z => z.Command.Name).Should().ContainInOrder("CodeLens 1", "CodeLens 2", "CodeLens 3");
+        }
+
         [Fact]
         public async Task Should_Behave_Like_An_Observable_With_WorkDone()
         {