How To Stop 3.0 From Creating New Track on Insert To Multitrack

My company still has us on AA3, which is fine -- I love it, except for one massively frustrating behavior I can't seem to find a solution for.  If I'm in the edit view, select part of an audio file and right-click>Insert To Multitrack, it inserts the file on a new track that it creates.  For example, if my session has five tracks and I do an Insert to Multitrack, now I have six tracks instead of inserting the clip someplace on one of the five existing tracks.  In previous versions, it wouldn't create a new track unless I specifically did so, and that's what I want.

This link -- Home Recording  -- suggests that there's a checkbox in the "Multitrack Clips section," but I can neither find that section, nor can I find any mention of it in a Google search.  My new(ish) computer rejects 1.5 for some reason, so there's no going back.  Anyone have an idea on how to stop this infuriating behavior?