Enhance Outlines with Accordion Functionality

Modern navigation includes accordion functionality when in a menu such as what we have with an Outline where making a second choice from the menu causes the original expanded branch to close, keeping the navigation tight and not forcing the user to have to close the open branch manually. While I respect that some designs may prefer to leave branches open, others may wish to have the choice to have them close automatically. I would like the ability to choose one or the other when creating an Outline. The default can function the same as today, and if you want the 'force collapse' feature you have to manually enable it.