allow not only deleting but also adding event to a section

[Zhang Weiwu]

Hello.

If I schedule a section, then the calendar entries of these events are created automatically. e.g. if I schedule a section over monday - friday morning, 5 events are created per week.
If I delete one of these events, the journal of that very day is deleted too, which is good. e.g. if I delete the event on 1st April, Thursday, then the journal page list April journal starting from 2nd April.

However there is no way to add an event in schedule. In working routine here we often need to add a complementary class, sometimes after a term time frame, more often than to delete one. It is also not very reasonable if a system allows deletion of pre-scheduled events but not allow adding.

This feature request requests allow the new event created associated with a section (offer to select one during creating the event). The added event does not only belong to the section in calendar, but also get itself a space in journal page.