fixes #99998 (#100233)

Author: sbatten

src/vs/platform/menubar/electron-main/menubar.ts

@@ -113,8 +113,8 @@ export class Menubar {
 	private addFallbackHandlers(): void {
 
 		// File Menu Items
-		this.fallbackMenuHandlers['workbench.action.files.newUntitledFile'] = (menuItem, win, event) => this.windowsMainService.openEmptyWindow({ context: OpenContext.MENU, contextWindowId: win.id });
-		this.fallbackMenuHandlers['workbench.action.newWindow'] = (menuItem, win, event) => this.windowsMainService.openEmptyWindow({ context: OpenContext.MENU, contextWindowId: win.id });
+		this.fallbackMenuHandlers['workbench.action.files.newUntitledFile'] = (menuItem, win, event) => this.windowsMainService.openEmptyWindow({ context: OpenContext.MENU, contextWindowId: win?.id });
+		this.fallbackMenuHandlers['workbench.action.newWindow'] = (menuItem, win, event) => this.windowsMainService.openEmptyWindow({ context: OpenContext.MENU, contextWindowId: win?.id });
 		this.fallbackMenuHandlers['workbench.action.files.openFileFolder'] = (menuItem, win, event) => this.electronMainService.pickFileFolderAndOpen(undefined, { forceNewWindow: this.isOptionClick(event), telemetryExtraData: { from: telemetryFrom } });
 		this.fallbackMenuHandlers['workbench.action.openWorkspace'] = (menuItem, win, event) => this.electronMainService.pickWorkspaceAndOpen(undefined, { forceNewWindow: this.isOptionClick(event), telemetryExtraData: { from: telemetryFrom } });