diff --git a/src/vs/workbench/api/browser/mainThreadComments.ts b/src/vs/workbench/api/browser/mainThreadComments.ts
index e9504bf27f5..c33593fd6e7 100644
--- a/src/vs/workbench/api/browser/mainThreadComments.ts
+++ b/src/vs/workbench/api/browser/mainThreadComments.ts
@@ -299,7 +299,8 @@ export class MainThreadCommentController {
 		this._features = features;
 	}
 
-	createCommentThread(commentThreadHandle: number,
+	createCommentThread(extensionId: string,
+		commentThreadHandle: number,
 		threadId: string,
 		resource: UriComponents,
 		range: IRange,
@@ -307,7 +308,7 @@ export class MainThreadCommentController {
 		let thread = new MainThreadCommentThread(
 			commentThreadHandle,
 			this.handle,
-			'',
+			extensionId,
 			threadId,
 			URI.revive(resource).toString(),
 			range
@@ -552,7 +553,8 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 		commentThreadHandle: number,
 		threadId: string,
 		resource: UriComponents,
-		range: IRange
+		range: IRange,
+		extensionId: ExtensionIdentifier
 	): modes.CommentThread2 | undefined {
 		let provider = this._commentControllers.get(handle);
 
@@ -560,7 +562,7 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 			return undefined;
 		}
 
-		return provider.createCommentThread(commentThreadHandle, threadId, resource, range);
+		return provider.createCommentThread(extensionId.value, commentThreadHandle, threadId, resource, range);
 	}
 
 	$updateCommentThread(handle: number,
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index ed5ae5e51a5..9f88aa946ab 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -136,7 +136,7 @@ export interface MainThreadCommentsShape extends IDisposable {
 	$registerCommentController(handle: number, id: string, label: string): void;
 	$unregisterCommentController(handle: number): void;
 	$updateCommentControllerFeatures(handle: number, features: CommentProviderFeatures): void;
-	$createCommentThread(handle: number, commentThreadHandle: number, threadId: string, resource: UriComponents, range: IRange): modes.CommentThread2 | undefined;
+	$createCommentThread(handle: number, commentThreadHandle: number, threadId: string, resource: UriComponents, range: IRange, extensionId: ExtensionIdentifier): modes.CommentThread2 | undefined;
 	$updateCommentThread(handle: number, commentThreadHandle: number, threadId: string, resource: UriComponents, range: IRange, label: string, contextValue: string | undefined, comments: modes.Comment[], acceptInputCommand: modes.Command | undefined, additionalCommands: modes.Command[], deleteCommand: modes.Command | undefined, collapseState: modes.CommentThreadCollapsibleState): void;
 	$deleteCommentThread(handle: number, commentThreadHandle: number): void;
 	$setInputValue(handle: number, input: string): void;
diff --git a/src/vs/workbench/api/common/extHostComments.ts b/src/vs/workbench/api/common/extHostComments.ts
index ca19cf7afcf..d10cb9a5325 100644
--- a/src/vs/workbench/api/common/extHostComments.ts
+++ b/src/vs/workbench/api/common/extHostComments.ts
@@ -592,7 +592,8 @@ export class ExtHostCommentThread implements vscode.CommentThread {
 		private _id: string | undefined,
 		private _uri: vscode.Uri,
 		private _range: vscode.Range,
-		private _comments: vscode.Comment[]
+		private _comments: vscode.Comment[],
+		extensionId: ExtensionIdentifier
 	) {
 		if (this._id === undefined) {
 			this._id = `${_commentController.id}.${this.handle}`;
@@ -603,7 +604,8 @@ export class ExtHostCommentThread implements vscode.CommentThread {
 			this.handle,
 			this._id,
 			this._uri,
-			extHostTypeConverter.Range.from(this._range)
+			extHostTypeConverter.Range.from(this._range),
+			extensionId
 		);
 
 		this._localDisposables = [];
@@ -751,7 +753,7 @@ class ExtHostCommentController implements vscode.CommentController {
 	}
 
 	constructor(
-		_extension: IExtensionDescription,
+		private _extension: IExtensionDescription,
 		private _handle: number,
 		private readonly _commandsConverter: CommandsConverter,
 		private _proxy: MainThreadCommentsShape,
@@ -765,18 +767,18 @@ class ExtHostCommentController implements vscode.CommentController {
 	createCommentThread(id: string, resource: vscode.Uri, range: vscode.Range, comments: vscode.Comment[]): vscode.CommentThread;
 	createCommentThread(arg0: vscode.Uri | string, arg1: vscode.Uri | vscode.Range, arg2: vscode.Range | vscode.Comment[], arg3?: vscode.Comment[]): vscode.CommentThread {
 		if (typeof arg0 === 'string') {
-			const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, arg0, arg1 as vscode.Uri, arg2 as vscode.Range, arg3 as vscode.Comment[]);
+			const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, arg0, arg1 as vscode.Uri, arg2 as vscode.Range, arg3 as vscode.Comment[], this._extension.identifier);
 			this._threads.set(commentThread.handle, commentThread);
 			return commentThread;
 		} else {
-			const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, undefined, arg0 as vscode.Uri, arg1 as vscode.Range, arg2 as vscode.Comment[]);
+			const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, undefined, arg0 as vscode.Uri, arg1 as vscode.Range, arg2 as vscode.Comment[], this._extension.identifier);
 			this._threads.set(commentThread.handle, commentThread);
 			return commentThread;
 		}
 	}
 
 	$createCommentThreadTemplate(uriComponents: UriComponents, range: IRange) {
-		const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, undefined, URI.revive(uriComponents), extHostTypeConverter.Range.to(range), []);
+		const commentThread = new ExtHostCommentThread(this._proxy, this._commandsConverter, this, undefined, URI.revive(uriComponents), extHostTypeConverter.Range.to(range), [], this._extension.identifier);
 		commentThread.collapsibleState = modes.CommentThreadCollapsibleState.Expanded;
 		this._threads.set(commentThread.handle, commentThread);
 		return commentThread;