Thanks for sharing your concerns.
As you know that GroupDocs.Annotation for Java 3.x is a UI and framework Independent (back-end) API. The showcase project you are talking about demonstrates basic functionalities of the API. Moreover, our showcase projects are open-source, you can add new features in them.
Please provide the latest showcase (downloadable) where are these features (tools and also annotations) work, which will help us.
Please note, concerned team releases regular updates of the showcase projects. But this process gets a bit slow when there are number of pending updates in the queue.
I've logged your scenario on GitHub, please keep track of this link
for further updates on it.