At some point there was code to detect when the window had focus, but this needs to be improved. The old client also had a "mark all messages as read" button and it has no equivalent in Banji.
This project is unfortunately no longer maintained. If a new maintainer wants to step up and take care, the project is archived here: https://invent.kde.org/network/ring-kde You can just clone it in your private namespace on invent.kde.org and if you have started to work on it and fixed/implemented something get it reviewed and the project unarchived. Sorry for the inconveniences.