Access to Calendar Items (Security Settings)
The items displayed in Office 365 Calendar Add-In are visible for calendar users according to SharePoint security settings. If there are special access settings for every SharePoint list’s items, they will be applied to these items in the Calendar.
For example, users with no access rights to items of List 1 will not see these items in the calendar. If they have rights of List 2 item management they can move, edit, resize these items in Office 365 Calendar Add-In. And if they have just read-only rights applied for List 3, they can view items of this list in the Calendar but have no ability to change any information of them (edit, resize, move, delete).