Non-visible buttons are still tabbable and read out by screenreaders

I've created an MR with a change for this. I've changed to use a hidden attribute rather than visually-hidden, but this is often overridden by a theme, so I've also added a display: none; inline style.

I've added the drupal cms a11y tag as well as wcag SC2.4.7 applies here as well. sighted keyboard users might get confused if on one tab no focus is visible. will manually test the MR over the weekend, but the proposed solution looks good from my perspective. and i've also set the priority back to normal.

I've tested the MR tonight. With the feature branch checked out the autosave button seems to be hidden and is not visible to sighted users nor screenreader users, but if i search for the class autosave-form-save in the web inspector i have no matches at all on the entire node edit form. so it seems like the autosave button isn't available at the moment? cuz there is also a deprecation error shown:

Deprecated function: Creation of dynamic property Drupal\autosave_form\Form\AutosaveFormBuilder::$_serviceId is deprecated in Drupal\Component\DependencyInjection\Container->createService() (line 285 of /var/www/html/repos/drupal/core/lib/Drupal/Component/DependencyInjection/Container.php).
Drupal\Component\DependencyInjection\Container->createService() (Line: 177)
Drupal\Component\DependencyInjection\Container->get() (Line: 430)
Drupal\Component\DependencyInjection\Container->resolveServicesAndParameters() (Line: 237)
Drupal\Component\DependencyInjection\Container->createService() (Line: 445)
Drupal\Component\DependencyInjection\Container->resolveServicesAndParameters() (Line: 237)
Drupal\Component\DependencyInjection\Container->createService() (Line: 177)
Drupal\Component\DependencyInjection\Container->get() (Line: 28)
Drupal\Core\DependencyInjection\ClassResolver->getInstanceFromDefinition() (Line: 100)
Drupal\Core\Utility\CallableResolver->getCallableFromDefinition() (Line: 34)
Drupal\Core\Controller\ControllerResolver->getControllerFromDefinition() (Line: 49)
Drupal\Core\Controller\ControllerResolver->getController() (Line: 166)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 32)
Drupal\big_pipe\StackMiddleware\ContentLength->handle() (Line: 116)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 90)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 709)
Drupal\Core\DrupalKernel->handle() (Line: 19)

tested on ddev on drupal 11.x and php 8.3. I'll set the issue back to needs work

@rkoller I tested the MR and I was able to see the autosave-form-save class in the DOM and also that the autosaving still works, as well as resuming from a draft or rejecting a draft.

Regarding the deprecation notice this was resolved with https://www.drupal.org/project/autosave_form/issues/3355495 🐛 PHP 8.2 deprecation issue with AutosaveFormBuilder Needs work some time ago.

I have merged the MR now.

Automatically closed - issue fixed for 2 weeks with no activity.