How do I get Jira Portfolio to respect existing sprints?

[Roy Levien]

When I try to create a plan in Jira Portfolio, Portfolio seems to pay no attention at all to the existing (and past) sprints for my project(s). It assigns issues that are already in an active sprint to sprints in the plan, and does not respect the calendar dates of the existing sprint in my project. 

How do I

1. get future sprints in Portfolio to start at the end of the current one for my project in Jira, 
2. keep the items in the current sprint there and not put them in future sprints, and (if possible), 
3. show past sprints?

[Belto]

The Scope view does not take into account closed Sprints.

To have more control over the future, past and current Sprints, you will have to use the Scope filters to define over what period of time the Plan should look at.

See Using scope filters for more details.