Opportunities displayed in Pipeline of Forecast Entry

We are running Sage 7.3b and getting ready to use the Forecast functionality.


However, we are confused as to why Opportunities that have already been Closed, Won, etc. show up in the Pipeline? Shouldn't the pipeline only display In Progress Opportunities? We have users with hundreds of opportunities and it's unwieldy to find only the In Progress ones to include in their forecast. See screenshot below. Is there something we're misunderstanding?

Thank you in advance,

~Cheryl