In bug 1445084 we're landing a migration of search results to use Fluent. One of the refactor pieces involves an element with a child we'd like to control from outside of Fluent. Based on the comments in the bug it seems that both Stas and I agree that we should add this feature, so I filed https://github.com/projectfluent/fluent.js/issues/169 Since the runtime-retranslation scenario is not supported yet in Firefox, and the potential bug is very minor (if a user manages to cause a runtime retranslation while the search results not found scenario is displayed, they'll loose the query), we're going to land it with a pointer to this bug and improve this logic here once we hash out the feature in FluentDOM.