Persistent notifications

Bq device, Ubuntu 14.10 (r20), Calendar app 0.4.623.

The notification time is definitely too short for me.

If I have my phone in the pocket and maybe I am talking with someone I would like to be able to see the notification or at least that something happened.
What happens now is that the phone vibrates in my pocket and then in the time that I say "I'm sorry" and take it out, the notification is gone and there is no way I can understand that that was actually the Calendar app (there is not a "notification history" to look at).

I think that the "Calendar" is not a "Reminder" app, the notification should stay there for as long as I don't remove it.
If I place something in the calendar is because I want to forget about it until it happens and then know what is happening, not because I want some mysterious ghost that makes my phone vibrate without further informations.

So, I guess that the best thing would be that the notifications are persistent and not fade away without the user being able to see them (like the Telegram, Gmail, ecc notifications).
Or at least an option to trigger it, because now the notifications are rather useless for me.