Diane Poremsky [MVP] wrote:
The ics calendar is not editable and new items will go to the other
calendar. You could switch to a table view, such as by category, select
all then use the Edit, Move to (or copy to) folder command to put the
appointments in your default calendar.


I removed the calendar I imported that way then re-imported it into the
native calendar. I've done some test appointments and it seems to work
fine. Thanks.