Messaging drawer close button missing

[Derryn Jones]

Moodle 3.6.1+ Adaptable 1.8.0

The messaging drawer does not have a visible 'close' button. The only way to close it is to click the button in the header or navigate away from the current page.

Looking at the source, there does seem to be a close button including an icon, but it doesn't seem to actually display anywhere:

<a id="message-drawer-close-5c5394a6a9fe85c5394a69426d374" class="" href="#">
            <img class="icon " alt="Toggle messaging drawer" title="Toggle messaging drawer" src="https://moodle.address/theme/image.php/adaptable/core/1548980721/i/window_close">
        </a>

[Info 3bits]

The drawer do not include any button to close as you can see when testing with Clean