Restore cursor position on #ajax 'input' or 'keyup' event

@Pancho Thank you for reporting this problem.

Is this issue still a problem? If so, can we have steps to reproduce.

Since we need more information to move forward with this issue, I am keeping the status at Postponed (maintainer needs more info). If we don't receive additional information to help with the issue, it may be closed after three months.

Thanks!

Code to reproduce:

  public function buildForm(array $form, FormStateInterface $form_state): array {
    $form['textfield'] = [
      '#type' => 'textfield',
      '#ajax' => [
        'callback' => '::ajaxUpdateTextfield',
        'event' => 'input',
        'wrapper' => 'textfield',
      ],
      '#prefix' => '<div id="textfield">',
      '#suffix' => '</div>',
    ];

    return $form;
  }

  public static function ajaxUpdateTextfield(array $form, FormStateInterface $form_state): array {
    return $form['textfield'];
  }

Video:

Thanks for the video @xandeadx that could be really annoying.

I implemented a failing test. But that test is inside a test function which is currently being skipped because of 📌 [random test failure] Re-enable AjaxTest::testAjaxFocus() Needs work .

Should this issue be dependent on the other one?

I implemented a fix and a test case. The test case is not run because of 📌 [random test failure] Re-enable AjaxTest::testAjaxFocus() Needs work . I'm not sure how to continue because the flaky tests in #3396536 📌 [random test failure] Re-enable AjaxTest::testAjaxFocus() Needs work seem to only be happening in the pipeline and I don't have enough expertise for that.

Have not reviewed yet but issue summary should be updated with standard template please.