Fix undo

src/view.tsx

@@ -32,6 +32,7 @@ import {
   regexIcon
 } from '@jupyterlab/ui-components';
 import type { CommandRegistry } from '@lumino/commands';
+import { PromiseDelegate } from '@lumino/coreutils';
 import { Message } from '@lumino/messaging';
 import React, { useEffect, useState } from 'react';
 import { AskBoolean } from './askBoolean';
@@ -491,9 +492,17 @@ export class SearchReplaceView extends VDomRenderer<SearchReplaceModel> {
     matches: SearchReplace.IReplacement[]
   ): Promise<IDocumentWidget<FileEditor>> {
     const widget = await this.openFile(path);
-    await widget.context.ready;
+    await Promise.all([widget.context.ready, widget.content.ready]);
+
     const editor = widget.content.editor as CodeMirrorEditor;
 
+    // Add arbitrary delay for the shared model to set up properly its undo manager
+    const waitForTimeout = new PromiseDelegate<void>();
+    window.setTimeout(() => {
+      waitForTimeout.resolve();
+    }, 300);
+    await waitForTimeout.promise;
+
     // Sort from end to start to preserve match positions
     matches
       .sort((a, b) => {

ui-tests/tests/replacePerItem.spec.ts

@@ -92,8 +92,7 @@ test('should replace results for a particular file only', async ({ page }) => {
   );
 });
 
-// FIXME
-test.skip('should undo replace results for a particular file only', async ({
+test('should undo replace results for a particular file only', async ({
   page
 }) => {
   await page.getByRole('tab', { name: 'Search and Replace' }).click();
@@ -229,8 +228,7 @@ test('should replace results for a particular match only', async ({ page }) => {
   );
 });
 
-// FIXME
-test.skip('should undo replace results for a particular match only', async ({
+test('should undo replace results for a particular match only', async ({
   page
 }) => {
   await page.getByRole('tab', { name: 'Search and Replace' }).click();

ui-tests/tests/search.spec.ts

@@ -271,7 +271,7 @@ test('should replace results on replace-all button', async ({ page }) => {
 
   await page
     .getByRole('textbox', { name: 'Search Files for Text' })
-    .fill('hello');
+    .fill('hola');
   await Promise.all([
     page.waitForResponse(
       response =>