I want to give a domain its own theme (company branding - that sort of thing).

Creating the theme is fine, I can pick it as user and it does the job.

But I want to set it to be the only theme accessible for all users in that domain.

So, on the admin console, I create a new Class of Service with the "Change UI" unchecked. In the CoS, I then go to the "Preferences" tab.

My new theme appears in the "Available UI themes" list. I can remove it to the "Installed UI themes" and add it back in again, so no problem there.

Where it doesn't appear at all, whatever else I do, is in the pop-up list for "Current UI theme" so I don't have the option to pick it as the one default theme for my CoS and so my domain.

Is this a bug, or is there something I might have done wrong?

(I followed these instructions to create the theme :