calendar-remove-frame-by-deleting

calendar-remove-frame-by-deleting is a variable defined in `calendar.el'.
Its value is

t

Documentation:
Determine how the calendar mode removes a frame no longer needed.
If nil, make an icon of the frame. If non-nil, delete the frame.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.1 of Emacs.