Description

When saving plugin while structure is open the mode switcher button disappears.

Steps to reproduce

1. Log in as a staff user
2. Go to any site in the cms
3. Open the structure
4. Edit a plugin
5. Save it
6. Wait for cms-content-refresh
7. Structure Button disappears

Expected behaviour

The Button should not disappear.

Actual behaviour

The Button disappears.
The div <div class="cms-toolbar-item-cms-mode-switcher"> is completely gone.

Additional information (CMS/Python/Django versions)

CMS 3.8.0
Python 3.9
Django 3.1.12