The story continues
I have tried to contact the author of that plugin, to ask him to continue his work. Unfortunately, without any success, I got no response at all. It’s sad to lose such a tiny but very useful piece of software. Therefore, I created my own copy of SubtaskDescription, I’ll maintain it from there.
You can download the first migrated version from here, there shouldn’t be any functional differences. Maybe you have to uninstall the original version first.
As usual, any feedback is highly appreciated.
@Rainer: This issue you reported above is WIP. 