📝 Provide detailed reproduction steps (if any)

1. Open any demo with menu bar, e.g. https://ckeditor.com/docs/ckeditor5/latest/examples/builds-custom/full-featured-editor.html
2. Disable a menu from menu bar typing editor.ui.view.menuBarView.menus[ 0 ].isEnabled = false; in the console.
3. Focus the editor.
4. Press Opt+F9 to focus menu bar.
5. Press "arrow down" when the disabled menu is focused.

✔️ Expected result

Nothing happens, menu should not be open.

❌ Actual result

Menu opens normally.

❓ Possible solution

If you have ideas, you can list them here. Otherwise, you can delete this section.

📃 Other details

• Browser: …
• OS: …
• First affected CKEditor version: …
• Installed CKEditor plugins: …

If you'd like to see this fixed sooner, add a 👍 reaction to this post.