smart step into doesn't work with scala?

Has anyone got "smart step into" to work with scala code?   It worked great on my java code, but not so for scala.   This feature is actually espeically useful for debugging scala code because multiple lines of java code often get compressed to a single line of scala.  But so far I have never been able to make it work for me.  Is there a setting somewhere that I am missing?  I am running idea 10.5.1 (IU-107.322) with scala plugin 0.4.1205.