Async error block not expandable

If I have an async block which returns a `xwikirenderingerror` div, once the async is resolved, the `xwikirenderingerror` is not clickable to expand it.

Example - with the office server offline, view this in a page:

{{async}}
{{office reference="Untitled2.odt"/}}
{{/async}}

It will give you a (seemingly) expandable error div, but you can't click it to see the description (stack trace).

I think a fix could be firing 'xwiki:dom:updated' somewhere here? - I didn't test this.