Hello!

The Aria theme does not have support for the UI mechanism. The lack of support was acknowledged in this comment for issue #1245: 3rd comment.

So, short answer is it is not supported currently. If you are using the Aria theme, do not use components's UI. You can still create a style to color components and bind the CSS style to that component, though.

Following, we've created a feature issue to implement UI support to the Aria theme, it is logged under #1439 and we'll update this thread as soon as we develop it.

Sorry for taking so long figuring out what the issue was, hope with the example of simplified code here, next time you'll be able to simplify your test case so we can quickly get to it and help you out.