I had hoped for a way to not show the dismiss button while it would be also not possible to swipe notifications off. I already pushed that dismiss button by accident. Without that button they would be super safe to stay. Another thing I found  cannot open a notification from the notification drawer where the event only contains an URL as the title  it says """"""""""""""""event not found"""""""""""""""". It seems reproducing this only requires to delete an event in Google Calendar  without dismissing it in Calendar Notifications Plus.""
October 29 2016