diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 93c361aa2a24b6a047abba03f35fb072c0cb5777..a882a05d59fbff6ba5b43acbc9f23e3d73167818 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -992,7 +992,7 @@ declare module 'vscode' {
 		 * @return A thenable that resolves to a list of commenting ranges or null and undefined if the provider
 		 * does not want to participate or was cancelled.
 		 */
-		registerCommentingRangeProvider(provider: (uri: Uri, token: CancellationToken) => ProviderResult<Range[]>, callback: (uri: Uri, range: Range) => void);
+		registerCommentingRangeProvider(provider: (document: TextDocument, token: CancellationToken) => ProviderResult<Range[]>, callback: (document: TextDocument, range: Range) => void);
 		dispose(): void;
 	}
 
diff --git a/src/vs/workbench/api/electron-browser/mainThreadComments.ts b/src/vs/workbench/api/electron-browser/mainThreadComments.ts
index e50af3509e04eac253df25193dc4c35567f3e8a8..7ef63a775e236c3f1321b95917b044f4027e67ed 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadComments.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadComments.ts
@@ -239,6 +239,13 @@ export class MainThreadCommentController {
 	updateComments(commentThreadHandle: number, comments: modes.Comment[]) {
 		let thread = this._threads.get(commentThreadHandle);
 		thread.comments = comments;
+
+		this._commentService.updateComments(`${this.handle}`, {
+			added: [],
+			removed: [],
+			changed: [thread],
+			draftMode: modes.DraftMode.NotSupported
+		});
 	}
 
 	updateAcceptInputCommands(commentThreadHandle: number, acceptInputCommands: modes.Command[]) {
@@ -289,6 +296,15 @@ export class MainThreadCommentController {
 		};
 	}
 
+	getAllComments(): MainThreadCommentThread[] {
+		let ret = [];
+		for (let thread of keys(this._threads)) {
+			ret.push(this._threads.get(thread));
+		}
+
+		return ret;
+	}
+
 	toJSON(): any {
 		return {
 			$mid: 6,
@@ -348,9 +364,13 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 		this._commentService.registerCommentController(String(handle), provider);
 		this._commentControllers.set(handle, provider);
 
+		const providerId = generateUuid();
+		this._handlers.set(handle, providerId);
+
 		const commentsPanelAlreadyConstructed = this._panelService.getPanels().some(panel => panel.id === COMMENTS_PANEL_ID);
 		if (!commentsPanelAlreadyConstructed) {
 			this.registerPanel(commentsPanelAlreadyConstructed);
+			this.registerOpenPanelListener(commentsPanelAlreadyConstructed);
 		}
 		this._commentService.setWorkspaceComments(String(handle), []);
 	}
@@ -466,6 +486,15 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 						});
 					});
 
+					keys(this._commentControllers).forEach(handle => {
+						let threads = this._commentControllers.get(handle).getAllComments();
+
+						if (threads.length) {
+							const providerId = this._handlers.get(handle);
+							this._commentService.setWorkspaceComments(providerId, threads);
+						}
+					});
+
 					if (this._openPanelListener) {
 						this._openPanelListener.dispose();
 						this._openPanelListener = null;
diff --git a/src/vs/workbench/api/node/extHostComments.ts b/src/vs/workbench/api/node/extHostComments.ts
index b6e04c85153d9faa6533acce87db08d060b23d4b..c4555575aa4bb05b201fe16aef5eefbcc6d54190 100644
--- a/src/vs/workbench/api/node/extHostComments.ts
+++ b/src/vs/workbench/api/node/extHostComments.ts
@@ -106,9 +106,10 @@ export class ExtHostComments implements ExtHostCommentsShape {
 			return Promise.resolve(undefined);
 		}
 
+		const document = this._documents.getDocument(URI.revive(uriComponents));
 		return asPromise(() => {
-			return commentController.commentingRangeProvider.provider(URI.revive(uriComponents), token);
-		}).then(ranges => ranges.map(extHostTypeConverter.Range.from));
+			return commentController.commentingRangeProvider.provider(document, token);
+		}).then(ranges => ranges ? ranges.map(extHostTypeConverter.Range.from) : undefined);
 	}
 
 	$createNewCommentWidgetCallback(commentControllerHandle: number, uriComponents: UriComponents, range: IRange, token: CancellationToken): void {
@@ -118,7 +119,8 @@ export class ExtHostComments implements ExtHostCommentsShape {
 			return;
 		}
 
-		commentController.commentingRangeProvider.callback(URI.revive(uriComponents), extHostTypeConverter.Range.to(range));
+		const document = this._documents.getDocument(URI.revive(uriComponents));
+		commentController.commentingRangeProvider.callback(document, extHostTypeConverter.Range.to(range));
 	}
 
 	registerWorkspaceCommentProvider(
@@ -412,8 +414,8 @@ export class ExtHostCommentInputBox implements vscode.CommentInputBox {
 
 class ExtHostCommentingRangeProvider {
 	constructor(
-		public provider: (uri: vscode.Uri, token: vscode.CancellationToken) => vscode.ProviderResult<vscode.Range[]>,
-		public callback: (uri: vscode.Uri, range: vscode.Range) => void
+		public provider: (document: vscode.TextDocument, token: vscode.CancellationToken) => vscode.ProviderResult<vscode.Range[]>,
+		public callback: (document: vscode.TextDocument, range: vscode.Range) => void
 	) {
 
 	}
@@ -464,7 +466,7 @@ class ExtHostCommentController implements vscode.CommentController {
 		return commentThread;
 	}
 
-	registerCommentingRangeProvider(provider: (uri: vscode.Uri, token: vscode.CancellationToken) => vscode.ProviderResult<vscode.Range[]>, callback: (uri: vscode.Uri, range: vscode.Range) => void) {
+	registerCommentingRangeProvider(provider: (document: vscode.TextDocument, token: vscode.CancellationToken) => vscode.ProviderResult<vscode.Range[]>, callback: (document: vscode.TextDocument, range: vscode.Range) => void) {
 		this._commentingRangeProvider = new ExtHostCommentingRangeProvider(provider, callback);
 	}
 
diff --git a/src/vs/workbench/contrib/comments/common/commentModel.ts b/src/vs/workbench/contrib/comments/common/commentModel.ts
index 8eed03dfcff659d7a1a7bb2ff1dbac67d7b45ff7..7a12bf1219714744c03165743fc5cd616ca49232 100644
--- a/src/vs/workbench/contrib/comments/common/commentModel.ts
+++ b/src/vs/workbench/contrib/comments/common/commentModel.ts
@@ -41,7 +41,7 @@ export class ResourceWithCommentThreads {
 	constructor(resource: URI, commentThreads: CommentThread[]) {
 		this.id = resource.toString();
 		this.resource = resource;
-		this.commentThreads = commentThreads.map(thread => ResourceWithCommentThreads.createCommentNode(resource, thread));
+		this.commentThreads = commentThreads.filter(thread => thread.comments.length).map(thread => ResourceWithCommentThreads.createCommentNode(resource, thread));
 	}
 
 	public static createCommentNode(resource: URI, commentThread: CommentThread): CommentNode {
@@ -99,14 +99,20 @@ export class CommentsModel {
 
 			// Find comment node on resource that is that thread and replace it
 			const index = firstIndex(matchingResourceData.commentThreads, (commentThread) => commentThread.threadId === thread.threadId);
-			matchingResourceData.commentThreads[index] = ResourceWithCommentThreads.createCommentNode(URI.parse(matchingResourceData.id), thread);
+			if (index >= 0) {
+				matchingResourceData.commentThreads[index] = ResourceWithCommentThreads.createCommentNode(URI.parse(matchingResourceData.id), thread);
+			} else {
+				matchingResourceData.commentThreads.push(ResourceWithCommentThreads.createCommentNode(URI.parse(matchingResourceData.id), thread));
+			}
 		});
 
 		added.forEach(thread => {
 			const existingResource = threadsForOwner.filter(resourceWithThreads => resourceWithThreads.resource.toString() === thread.resource);
 			if (existingResource.length) {
 				const resource = existingResource[0];
-				resource.commentThreads.push(ResourceWithCommentThreads.createCommentNode(resource.resource, thread));
+				if (thread.comments.length) {
+					resource.commentThreads.push(ResourceWithCommentThreads.createCommentNode(resource.resource, thread));
+				}
 			} else {
 				threadsForOwner.push(new ResourceWithCommentThreads(URI.parse(thread.resource), [thread]));
 			}