\fromproperty return problem.

[Gilles THIBAULT]

I just try the  version "2.11.40" and his new markup command : \underline.
I am very happy with it but i have a problem using it with the \fromproperty
command.
In the score above, there is no title defined in the score header but you 
can see a line above
the note :

   { c'1^\markup { \underline \fromproperty #'header:title } }

It seems that \fromproperty doesn't return an empty stencil, even if the 
property given in the argument is empty.
It becomes a problem in a book with several scores,  if you defines a 
scoreTitleMarkup for example  in a way like that

\paper {
   scoreTitleMarkup = \markup {
       printallheaders=##t
       ................
      ....\underline \fromproperty #'header:subsubtitle
       ................
       }
   }
}

because if a score has no subsubtitle, you'll get a (under)line !

Is there a workaround for that ?

Gilles