figured base does not track notes in staff

[Alan Jones]

I took the following example from the documentation, but added 
the tailing g's.  No matter how many notes are cramed into the
line, the figures remain in the same place.  Aren't the figures 
supposed to track with the notes similar to lyrics?
Alan

\version "2.10.17"
\new Voice { 
  \clef bass dis4 c d ais g fis g g g g g g g g g g g g g
}
\new FiguredBass \figuremode {
  <6>4 <7\+>8 <6+ [_!]>
  <6>4 <6 5 [3+]>
  <_>4 <6 5/>4
}