### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

12.0.5

### What operating system are you using?

macOS

### Operating System Version

11.2.3

### What arch are you using?

arm64 (including Apple Silicon)

### Last Known Working Electron version

_No response_

### Expected Behavior

`document.hasFocus()` is only `true` for the window that has focus.

### Actual Behavior

Ever window reports `document.hasFocus()` to be `true` right after opening.

### Testcase Gist URL

https://gist.github.com/16e6fc829febd0cab115dfd0850a31be

### Additional Information

_No response_
shell/browser/api/electron_api_web_contents.cc
const std::string& content) {
  auto it = saved_files_.find(url);
  if (it == saved_files_.end())
    return;
   Notify DevTools.
  base::Value url_value(url);
  inspectable_ontents_->CallClientFunction("DevToolsAPI.appendedToURL",
                                                &url_value, nullptr, nullptr);
  file_task_runner_->PostTask(
      FROM_HERE, base::BindOnce(&AppendToFile, it->second, content));
}
void WebContents::DevToolsRequestFileSystems() {