Fixes microsoft/monaco-editor#2339: Listen to focusin and focusout and refresh the dom focus tracker state

src/vs/base/browser/dom.ts

@@ -908,7 +908,7 @@ export const EventHelper = {
 export interface IFocusTracker extends Disposable {
 	onDidFocus: Event<void>;
 	onDidBlur: Event<void>;
-	refreshState?(): void;
+	refreshState(): void;
 }
 
 export function saveParentsScrollTop(node: Element): number[] {

src/vs/editor/browser/widget/codeEditorWidget.ts

@@ -2007,6 +2007,12 @@ class CodeEditorWidgetFocusTracker extends Disposable {
 			this._hasFocus = false;
 			this._onChange.fire(undefined);
 		}));
+		this._register(dom.addDisposableListener(domElement, 'focusin', () => {
+			this._domFocusTracker.refreshState();
+		}));
+		this._register(dom.addDisposableListener(domElement, 'focusout', () => {
+			this._domFocusTracker.refreshState();
+		}));
 	}
 
 	public hasFocus(): boolean {