\breakDynamicSpan breaks with \break ("bounds of spanner are invalid")

[Reinhold Kainhofer]

The regtest input/regression/dynamics-alignment-breaker.ly for 
\breakDynamicSpan works fine, but as soon as there are line breaks during a 
dynamic spanner, it breaks with error messages:

Programmierfehler: Spanner `Hairpin' is not fully contained in parent spanner. 
Ignoring orphaned part
Programmierfehler: bounds of spanner are invalid


Here is a non-working modification of the regtest:

\version "2.13.23"

\header {
  texidoc = "Hairpins, DynamicTextSpanners and dynamics can be
positioned independently using @code{\\breakDynamicSpan}, which
causes the alignment spanner to end prematurely.
"
}

\relative c' {
  c1^\< \break
  \dimTextDim
  c1_\>
  f,1\p

  \break

  c'1^\<
  \breakDynamicSpan \break
  c1_\>
  \breakDynamicSpan
  f,1\p
}


Cheers,
Reinhold
-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org