diff --git a/extensions/git-extended/src/review/reviewMode.ts b/extensions/git-extended/src/review/reviewMode.ts
index 41bf6822913..fda563252f2 100644
--- a/extensions/git-extended/src/review/reviewMode.ts
+++ b/extensions/git-extended/src/review/reviewMode.ts
@@ -214,6 +214,9 @@ export class ReviewMode implements vscode.DecorationProvider {
 			// No old threads match this thread, it is new
 			if (matchingCommentThread.length === 0) {
 				added.push(thread);
+				if (thread.resource.scheme === 'file') {
+					thread.collapsibleState = vscode.CommentThreadCollapsibleState.Collapsed;
+				}
 			}
 
 			// Check if comment has been updated
@@ -267,7 +270,7 @@ export class ReviewMode implements vscode.DecorationProvider {
 		return Promise.resolve(null);
 	}
 
-	private commentsToCommentThreads(comments: Comment[]): vscode.CommentThread[] {
+	private commentsToCommentThreads(comments: Comment[], collapsibleState: vscode.CommentThreadCollapsibleState = vscode.CommentThreadCollapsibleState.Expanded): vscode.CommentThread[] {
 		if (!comments || !comments.length) {
 			return [];
 		}
@@ -297,6 +300,7 @@ export class ReviewMode implements vscode.DecorationProvider {
 						gravatar: comment.user.avatar_url
 					};
 				}),
+				collapsibleState: collapsibleState,
 				reply: this._reply
 			});
 		}
@@ -361,7 +365,7 @@ export class ReviewMode implements vscode.DecorationProvider {
 				}
 
 				return {
-					threads: this.commentsToCommentThreads(matchingComments),
+					threads: this.commentsToCommentThreads(matchingComments, document.uri.scheme === 'file' ? vscode.CommentThreadCollapsibleState.Collapsed : vscode.CommentThreadCollapsibleState.Expanded),
 					commentingRanges: ranges,
 					reply: this._reply
 				};
diff --git a/src/vs/editor/common/modes.ts b/src/vs/editor/common/modes.ts
index e52dc256ec6..20c106667a6 100644
--- a/src/vs/editor/common/modes.ts
+++ b/src/vs/editor/common/modes.ts
@@ -944,12 +944,24 @@ export interface CommentInfo {
 	reply?: Command;
 }
 
+export enum CommentThreadCollapsibleState {
+	/**
+	 * Determines an item is collapsed
+	 */
+	Collapsed = 0,
+	/**
+	 * Determines an item is expanded
+	 */
+	Expanded = 1
+}
+
 export interface CommentThread {
-	readonly threadId: string;
-	readonly resource: string;
-	readonly range: IRange;
-	readonly comments: Comment[];
-	readonly reply: Command;
+	threadId: string;
+	resource: string;
+	range: IRange;
+	comments: Comment[];
+	collapsibleState?: CommentThreadCollapsibleState;
+	reply?: Command;
 }
 
 export interface NewCommentAction {
diff --git a/src/vs/editor/standalone/browser/standaloneLanguages.ts b/src/vs/editor/standalone/browser/standaloneLanguages.ts
index c0eec9275ac..e3f74519604 100644
--- a/src/vs/editor/standalone/browser/standaloneLanguages.ts
+++ b/src/vs/editor/standalone/browser/standaloneLanguages.ts
@@ -793,6 +793,7 @@ export function createMonacoLanguagesAPI(): typeof monaco.languages {
 		CompletionItemKind: CompletionItemKind,
 		SymbolKind: modes.SymbolKind,
 		IndentAction: IndentAction,
-		SuggestTriggerKind: modes.SuggestTriggerKind
+		SuggestTriggerKind: modes.SuggestTriggerKind,
+		CommentThreadCollapsibleState: modes.CommentThreadCollapsibleState
 	};
 }
diff --git a/src/vs/monaco.d.ts b/src/vs/monaco.d.ts
index 94ec028e521..fce9dddf1a9 100644
--- a/src/vs/monaco.d.ts
+++ b/src/vs/monaco.d.ts
@@ -5035,12 +5035,24 @@ declare namespace monaco.languages {
 		reply?: Command;
 	}
 
+	export enum CommentThreadCollapsibleState {
+		/**
+		 * Determines an item is collapsed
+		 */
+		Collapsed = 0,
+		/**
+		 * Determines an item is expanded
+		 */
+		Expanded = 1,
+	}
+
 	export interface CommentThread {
-		readonly threadId: string;
-		readonly resource: string;
-		readonly range: IRange;
-		readonly comments: Comment[];
-		readonly reply: Command;
+		threadId: string;
+		resource: string;
+		range: IRange;
+		comments: Comment[];
+		collapsibleState?: CommentThreadCollapsibleState;
+		reply?: Command;
 	}
 
 	export interface NewCommentAction {
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index fa0a8afc25f..bffc6b40294 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -776,11 +776,23 @@ declare module 'vscode' {
 		reply?: Command;
 	}
 
+	export enum CommentThreadCollapsibleState {
+		/**
+		 * Determines an item is collapsed
+		 */
+		Collapsed = 0,
+		/**
+		 * Determines an item is expanded
+		 */
+		Expanded = 1
+	}
+
 	interface CommentThread {
 		threadId: string;
 		resource: Uri;
 		range: Range;
 		comments: Comment[];
+		collapsibleState?: CommentThreadCollapsibleState;
 		reply?: Command;
 	}
 
diff --git a/src/vs/workbench/api/electron-browser/mainThreadComments.ts b/src/vs/workbench/api/electron-browser/mainThreadComments.ts
index d5020a8e37f..919a4fbddb9 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadComments.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadComments.ts
@@ -47,6 +47,10 @@ export class MainThreadComments extends Disposable implements MainThreadComments
 				return;
 			}
 
+			if (!outerEditor.getModel()) {
+				return;
+			}
+
 			const outerEditorURI = outerEditor.getModel().uri;
 			this.provideComments(outerEditorURI).then(commentInfos => {
 				this._commentService.setComments(outerEditorURI, commentInfos);
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index fb249f99481..7961f1aad94 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -686,7 +686,9 @@ export function createApiFactory(
 			FileType: extHostTypes.FileType,
 			FoldingRangeList: extHostTypes.FoldingRangeList,
 			FoldingRange: extHostTypes.FoldingRange,
-			FoldingRangeType: extHostTypes.FoldingRangeType
+			FoldingRangeType: extHostTypes.FoldingRangeType,
+
+			CommentThreadCollapsibleState: extHostTypes.CommentThreadCollapsibleState
 		};
 	};
 }
diff --git a/src/vs/workbench/api/node/extHostComments.ts b/src/vs/workbench/api/node/extHostComments.ts
index 570e7b19376..8ebbf34b5aa 100644
--- a/src/vs/workbench/api/node/extHostComments.ts
+++ b/src/vs/workbench/api/node/extHostComments.ts
@@ -103,6 +103,7 @@ function convertCommentThread(vscodeCommentThread: vscode.CommentThread, command
 		resource: vscodeCommentThread.resource.toString(),
 		range: extHostTypeConverter.fromRange(vscodeCommentThread.range),
 		comments: vscodeCommentThread.comments.map(convertComment),
+		collapsibleState: vscodeCommentThread.collapsibleState,
 		reply: vscodeCommentThread.reply ? commandsConverter.toInternal(vscodeCommentThread.reply) : null
 	};
 }
diff --git a/src/vs/workbench/api/node/extHostTypes.ts b/src/vs/workbench/api/node/extHostTypes.ts
index def9661a41d..5298e7c06b5 100644
--- a/src/vs/workbench/api/node/extHostTypes.ts
+++ b/src/vs/workbench/api/node/extHostTypes.ts
@@ -1868,3 +1868,15 @@ export enum FoldingRangeType {
 }
 
 //#endregion
+
+
+export enum CommentThreadCollapsibleState {
+	/**
+	 * Determines an item is collapsed
+	 */
+	Collapsed = 0,
+	/**
+	 * Determines an item is expanded
+	 */
+	Expanded = 1
+}
\ No newline at end of file
diff --git a/src/vs/workbench/parts/comments/electron-browser/commentsEditorContribution.ts b/src/vs/workbench/parts/comments/electron-browser/commentsEditorContribution.ts
index 8797d4ad3aa..5b8adb82f50 100644
--- a/src/vs/workbench/parts/comments/electron-browser/commentsEditorContribution.ts
+++ b/src/vs/workbench/parts/comments/electron-browser/commentsEditorContribution.ts
@@ -102,6 +102,9 @@ export class CommentNode {
 	}
 }
 
+const EXPAND_ACTION_CLASS = 'expand-review-action octicon octicon-chevron-down';
+const COLLAPSE_ACTION_CLASS = 'expand-review-action octicon octicon-chevron-up';
+
 export class ReviewZoneWidget extends ZoneWidget {
 	private _headElement: HTMLElement;
 	protected _primaryHeading: HTMLElement;
@@ -113,7 +116,7 @@ export class ReviewZoneWidget extends ZoneWidget {
 	private _commentElements: CommentNode[];
 	private _resizeObserver: any;
 	private _onDidClose = new Emitter<ReviewZoneWidget>();
-	private _isCollapsed = true;
+	private _isCollapsed;
 	private _toggleAction: Action;
 	private _commentThread: modes.CommentThread;
 	public get commentThread(): modes.CommentThread {
@@ -139,6 +142,7 @@ export class ReviewZoneWidget extends ZoneWidget {
 		this._owner = owner;
 		this._commentThread = commentThread;
 		this._replyCommand = replyCommand;
+		this._isCollapsed = commentThread.collapsibleState !== modes.CommentThreadCollapsibleState.Expanded;
 		this.create();
 		this.themeService.onThemeChange(this._applyTheme, this);
 	}
@@ -183,15 +187,15 @@ export class ReviewZoneWidget extends ZoneWidget {
 		this._actionbarWidget = new ActionBar(actionsContainer.getHTMLElement(), {});
 		this._disposables.push(this._actionbarWidget);
 
-		this._toggleAction = new Action('review.expand', nls.localize('label.expand', "Expand"), 'expand-review-action octicon octicon-chevron-down', true, () => {
+		this._toggleAction = new Action('review.expand', nls.localize('label.expand', "Expand"), this._isCollapsed ? EXPAND_ACTION_CLASS : COLLAPSE_ACTION_CLASS, true, () => {
 			if (this._isCollapsed) {
 				this._bodyElement.style.display = 'block';
-				this._toggleAction.class = 'expand-review-action octicon octicon-chevron-up';
+				this._toggleAction.class = COLLAPSE_ACTION_CLASS;
 				this._isCollapsed = false;
 			}
 			else {
 				this._bodyElement.style.display = 'none';
-				this._toggleAction.class = 'expand-review-action octicon octicon-chevron-down';
+				this._toggleAction.class = EXPAND_ACTION_CLASS;
 				this._isCollapsed = true;
 			}
 			return null;
@@ -270,7 +274,7 @@ export class ReviewZoneWidget extends ZoneWidget {
 		this._headElement.style.height = `${headHeight}px`;
 		this._headElement.style.lineHeight = this._headElement.style.height;
 
-		this._bodyElement.style.display = 'none';
+		this._bodyElement.style.display = this._isCollapsed ? 'none' : 'block';
 		this._commentsElement = $('div.comments-container').appendTo(this._bodyElement).getHTMLElement();
 		this._commentElements = [];
 		for (let i = 0; i < this._commentThread.comments.length; i++) {