Seems to work on 3.26.1

Capture d’écran_2021-05-05_15-28-53.png (25,073 bytes)   

Capture d’écran_2021-05-05_15-28-53.png (25,073 bytes)   

Capture d’écran_2021-05-05_15-29-10.png (80,803 bytes)   

Capture d’écran_2021-05-05_15-29-10.png (80,803 bytes)   

The menu works. However, I would have expected that with the right permissions the theme tile on the main screen would also be visible.

themes.png (3,439 bytes)   

themes.png (3,439 bytes)   

OK ,

Confirm the issue,
(in my opinion) it's more e feature request because Complex permission check are not implemented on Boxes.

Agreed, as the menu is working, this is a feature request.