Current behavior for having SAMIGO add a quiz due date to the calendar:

• Instructor creates a quiz in Tests & Quizzes.

• Instructor goes in to Settings and configured open date, due date, and all other options.

• Instructor publishes the quiz

• On the publish page, instructor checks/unchecks the box to add the due date to the calendar. 

After the quiz is published, the only way to change whether it is added to the calendar is to retract & republish the quiz. 

I propose having the "Add due date to Calendar" checkbox in the Settings page itself, as part of the "Availability and Submissions" section. This should: 

• Allow the instructor to set whether a quiz due date should be on the calendar or not before it is published.

• Have that setting persist on duplicate/import, like the other quiz settings.

• Be changed on published copies without needing to retract the quiz.