Fix initial comment expand state (microsoft#180941)

Fixes microsoft#169928

Author: alexr00

src/vs/workbench/contrib/comments/browser/commentThreadWidget.ts

@@ -34,7 +34,7 @@ export const COMMENTEDITOR_DECORATION_KEY = 'commenteditordecoration';
 
 export class CommentThreadWidget<T extends IRange | ICellRange = IRange> extends Disposable implements ICommentThreadWidget {
 	private _header!: CommentThreadHeader<T>;
-	private _body!: CommentThreadBody<T>;
+	private _body: CommentThreadBody<T>;
 	private _commentReply?: CommentReply<T>;
 	private _additionalActions?: CommentThreadAdditionalActions<T>;
 	private _commentMenus: CommentMenus;
@@ -274,7 +274,7 @@ export class CommentThreadWidget<T extends IRange | ICellRange = IRange> extends
 	}
 
 	getDimensions() {
-		return this._body?.getDimensions();
+		return this._body.getDimensions();
 	}
 
 	layout(widthInPixel?: number) {

src/vs/workbench/contrib/comments/browser/commentThreadZoneWidget.ts

@@ -416,8 +416,12 @@ export class ReviewZoneWidget extends ZoneWidget implements ICommentThreadWidget
 		this._commentThreadWidget.submitComment();
 	}
 
-	_refresh(dimensions?: dom.Dimension) {
-		if (this._isExpanded && dimensions) {
+	_refresh(dimensions: dom.Dimension) {
+		if (dimensions.height === 0 && dimensions.width === 0) {
+			this.commentThread.collapsibleState = languages.CommentThreadCollapsibleState.Collapsed;
+			return;
+		}
+		if (this._isExpanded) {
 			this._commentThreadWidget.layout();
 
 			const headHeight = Math.ceil(this.editor.getOption(EditorOption.lineHeight) * 1.2);