When a teacher decides to restrict access of an activity (any), 2 choices are available:
1. Show activity grey-out, with restricted information
2. Hide activity entirely
With option number 1, when restricting "from" and "until" a certain date, the activity will disappear when the "until" date as been reached. Is it not suppose to simply grey it out ? By disappearing, the students cannot even access the activity because it's not there anymore. Is this intentional ?