Fix comments memory leak (#213542)

Fixes #213535

Author: alexr00

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

@@ -65,6 +65,7 @@ export class CommentThreadHeader<T = IRange> extends Disposable {
 		this._collapseAction = new Action('review.expand', nls.localize('label.collapse', "Collapse"), COLLAPSE_ACTION_CLASS, true, () => this._delegate.collapse());
 
 		const menu = this._commentMenus.getCommentThreadTitleActions(this._contextKeyService);
+		this._register(menu);
 		this.setActionBarActions(menu);
 
 		this._register(menu);

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

@@ -88,7 +88,7 @@ export class CommentThreadWidget<T extends IRange | ICellRange = IRange> extends
 
 		this._commentMenus = this.commentService.getCommentMenus(this._owner);
 
-		this._header = new CommentThreadHeader<T>(
+		this._register(this._header = new CommentThreadHeader<T>(
 			container,
 			{
 				collapse: this.collapse.bind(this)
@@ -98,7 +98,7 @@ export class CommentThreadWidget<T extends IRange | ICellRange = IRange> extends
 			this._contextKeyService,
 			this._scopedInstantiationService,
 			contextMenuService
-		);
+		));
 
 		this._header.updateCommentThread(this._commentThread);