When creating a reminder for tasks/comments, there is no save/create button. It looks like the reminder is created when you click outside the calender. But there is also no notification or something when you do this. The only way to know that the reminder is created is by going to the 'home' screen and see it under 'my work'.

I would suggest to add a save/create button when creating a reminder for a task/comment and to add a notification when it is created.