I cannot see the Related To information when viewing another user’s calendar.
|Knowledge Article Number||000003630|
When I view my own calendar, Events which are related to another record display that related record next to the Event Name and Location. When I view another user's calendar, I only see the Event Name and Location, not the related record.
This is an expected behavior. You will only see the record the Event is related to when viewing entries on your own calendar, not when viewing other user's calendars.
To work around this, include the "Related To" field in the Event Hover Details (See "Defining Mini Page Layouts").