\partcombine and \setTextCresc

[Frédéric Bron]

In the following example, the crescendo has airpins instead of text. 
Everything is fine if \partcombine is replaced by polyphony <<  ... \\ 
... >>.

\version "2.6.4"
\include "english.ly"

\score {
       \partcombine
       {
               \setTextCresc
               r4 c'\< r d'
               e'\!\f
       }
       {
               R1*1
               c'4\f
       }
}