[Regression]: Pressing Tab in Firefox does not trigger blur event

[sissbruecker]

Last Good Version

1.43.1

First Bad Version

1.44.0

Steps to reproduce

1. Clone repo at https://github.com/sissbruecker/playwright-firefox-blur-on-tab-regression
2. Run npm install
3. Run npx playwright install firefox
4. Run npx playwright test

Expected behavior

The test should pass.

For reference, the test setup:

<label for="test">test</label>
<input id="test">

<script>
  const input = document.getElementById('test');
  input.addEventListener('blur', () => {
    const text = document.createElement('p');
    text.textContent = "Input was blurred";
    document.body.appendChild(text);
  })
</script>

And the the test:

  await page.goto('/');
  await page.getByLabel("test").click();
  await page.keyboard.press("Tab");

  await expect(page.getByText("Input was blurred")).toBeVisible();

Actual behavior

The last assertion fails because the blur listener did not run.

Additional context

• The issue is still present in 1.46.1.
• The test setup is in index.html
• From debugging this it looks like focus changes but the blur event is not fired.
• The test works with Chromium
• The test fails with Webkit, though the regression seems to have been introduced earlier for Webkit

Environment

System:
    OS: macOS 13.6
    CPU: (10) arm64 Apple M1 Pro
    Memory: 2.77 GB / 32.00 GB
  Binaries:
    Node: 20.9.0 - /var/folders/m0/_cm1wj395tq_4r1nqwq5dg2h0000gn/T/fnm_multishells/75765_1724762438045/bin/node
    Yarn: 1.22.22 - /var/folders/m0/_cm1wj395tq_4r1nqwq5dg2h0000gn/T/fnm_multishells/75765_1724762438045/bin/yarn
    npm: 10.1.0 - /var/folders/m0/_cm1wj395tq_4r1nqwq5dg2h0000gn/T/fnm_multishells/75765_1724762438045/bin/npm
  Languages:
    Bash: 3.2.57 - /bin/bash
  npmPackages:
    @playwright/test: 1.44.0 => 1.44.0

[yury-s]

Failing in WebKit too.