Summary cannot be styled

Problem/Motivation

Hi everyone, when you try to add a style or element inside the summary the button is disabled like in the image you can see below. I think the error is linked to CKEditor5 switch.

Steps to reproduce

Add a content type that have a field like standard html or full html text type and then try to add a style or formatting to detail's summary.

I think the error is because the summary, in ckeditor5, isn't an inline editable element.

But if you try to edit the allowContentOf: form $block to $root it became editable but the layout goes away.

    schema.register('detailSummary', {
      // This creates a boundary for external actions such as clicking and
      // and keypress. For example, when the cursor is inside this box, the
      // keyboard shortcut for "select all" will be limited to the contents of
      // the box.
      isLimit: true,
      // This is only to be used within detail.
      allowIn: 'detail',
      // Allow content that is allowed in blocks (e.g. text with attributes).
      allowContentOf: '$block',
    });

In the previous versions of the module, before the ckeditor5 upgrade, it works fine.
If you try to remove plugin from ckeditor toolbar and then paste the code that the plugin outputs, it works fine.

Any idea?