slur problem

[info]

I have gotten this to work in score but not in the part

\version "2.18.0"
horn = \relative c,
{
\clef "bass_8"
\key c \major
\time 4/4
fis,1
  \time 3/4
  (d'2.)
  \bar "|."
  }
  \score {
\new Staff \horn
\layout {
 }
}

the slur from fis1 to the d'2. doesn't work here but did in the full 
score.  So what do I do to make this work in the part?
Thanks
Jay