TrillSpanner does not extend over tied note

[Kieren MacMillan]

[Mac OS X 10.4.11]

Notice that the TrillSpanner does not extend through (i.e., include)  
the tied note, as expected/desired:

\version "2.12.2"
\paper { ragged-right = ##f }
trillBugMusic = \relative c'
{
  c1\startTrillSpan ~ |
  c4 c\stopTrillSpan\startTrillSpan ~ c c\stopTrillSpan 
\startTrillSpan ~ |
  c1\stopTrillSpan
}
\score { \trillBugMusic }

Cheers,
Kieren.