From 1d618b2df1cf08f0e3ab706353f0a8f6f1424795 Mon Sep 17 00:00:00 2001
From: Rob Lourens <roblourens@gmail.com>
Date: Thu, 17 Feb 2022 20:12:09 -0800
Subject: [PATCH] Don't cache the state from focusTracker. Check activeElement
 directly when you need to know the current focus state. Fix #141676

---
 .../notebook/browser/notebookEditorWidget.ts  | 68 +++++--------------
 1 file changed, 18 insertions(+), 50 deletions(-)

diff --git a/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts b/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
index cf6f48912b1..3bec30006e2 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
+++ b/src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts
@@ -233,41 +233,6 @@ export function getDefaultNotebookCreationOptions() {
 	};
 }
 
-class NotebookEditorWidgetFocusTracker extends Disposable {
-
-	private _hasFocus: boolean;
-	private readonly _domFocusTracker: DOM.IFocusTracker;
-
-	private readonly _onChange: Emitter<void> = this._register(new Emitter<void>());
-	public readonly onChange: Event<void> = this._onChange.event;
-
-	constructor(domElement: HTMLElement) {
-		super();
-
-		this._hasFocus = false;
-		this._domFocusTracker = this._register(DOM.trackFocus(domElement));
-
-		this._register(this._domFocusTracker.onDidFocus(() => {
-			this._hasFocus = true;
-			this._onChange.fire(undefined);
-		}));
-		this._register(this._domFocusTracker.onDidBlur(() => {
-			this._hasFocus = false;
-			this._onChange.fire(undefined);
-		}));
-	}
-
-	public hasFocus(): boolean {
-		return this._hasFocus;
-	}
-
-	public refreshState(): void {
-		if (this._domFocusTracker.refreshState) {
-			this._domFocusTracker.refreshState();
-		}
-	}
-}
-
 export class NotebookEditorWidget extends Disposable implements INotebookEditorDelegate, INotebookEditor {
 	//#region Eventing
 	private readonly _onDidChangeCellState = this._register(new Emitter<NotebookCellStateChangedEvent>());
@@ -337,7 +302,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditorD
 	private _cellContextKeyManager: CellContextKeyManager | null = null;
 	private _isVisible = false;
 	private readonly _uuid = generateUuid();
-	private _widgetFocusTracker!: NotebookEditorWidgetFocusTracker;
+	private _focusTracker!: DOM.IFocusTracker;
 	private _webviewFocused: boolean = false;
 
 	private _isDisposed: boolean = false;
@@ -1049,17 +1014,16 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditorD
 			}
 		}));
 
-		this._widgetFocusTracker = this._register(new NotebookEditorWidgetFocusTracker(this.getDomNode()));
-		this._register(this._widgetFocusTracker.onChange(() => {
-			const focused = this._widgetFocusTracker.hasFocus();
-			this._editorFocus.set(focused);
-			this.viewModel?.setEditorFocus(focused);
-
-			if (focused) {
-				this._onDidFocusEmitter.fire();
-			} else {
-				this._onDidBlurEmitter.fire();
-			}
+		this._focusTracker = this._register(DOM.trackFocus(this.getDomNode()));
+		this._register(this._focusTracker.onDidBlur(() => {
+			this._editorFocus.set(false);
+			this.viewModel?.setEditorFocus(false);
+			this._onDidBlurEmitter.fire();
+		}));
+		this._register(this._focusTracker.onDidFocus(() => {
+			this._editorFocus.set(true);
+			this.viewModel?.setEditorFocus(true);
+			this._onDidFocusEmitter.fire();
 		}));
 
 		this._registerNotebookActionsToolbar();
@@ -1863,11 +1827,15 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditorD
 		this._notebookTopToolbarContainer.style.display = 'none';
 	}
 
+	private editorHasDomFocus(): boolean {
+		return DOM.isAncestor(document.activeElement, this.getDomNode());
+	}
+
 	updateEditorFocus() {
 		// Note - focus going to the webview will fire 'blur', but the webview element will be
 		// a descendent of the notebook editor root.
-		this._widgetFocusTracker.refreshState();
-		const focused = this._widgetFocusTracker.hasFocus();
+		this._focusTracker.refreshState();
+		const focused = this.editorHasDomFocus();
 		this._editorFocus.set(focused);
 		this.viewModel?.setEditorFocus(focused);
 	}
@@ -1876,7 +1844,7 @@ export class NotebookEditorWidget extends Disposable implements INotebookEditorD
 		// _editorFocus is driven by the FocusTracker, which is only guaranteed to _eventually_ fire blur.
 		// If we need to know whether we have focus at this instant, we need to check the DOM manually.
 		this.updateEditorFocus();
-		return this._widgetFocusTracker.hasFocus();
+		return this.editorHasDomFocus();
 	}
 
 	hasWebviewFocus() {