Hi @m.zsolnay, welcome to the Community 
I saw your post on GitHub… you really shouldn’t post this sort of thing there - it’s just for developers to work on fixes, not for end-user support.
And for the Forums, it’s best to open your own thread, and follow the
About what you ask, I don’t think it’s a standard feature, sorry. Maybe it could be achieved with a code fix, although I don’t really know how to advise you on that one. To be honest I didn’t know that you could see tasks in the Calendar, I thought it was only for appointments and meetings!
Cheers