including gregorian.ly breaks lyrics alignment in melismas

[Janek Warchoł]

Hi,

Search for "gregorian" in tracker didn't show any results like this,
so i report:
including gregorian.ly breaks horizontal spacing when there are lyrics. Example:

\include "gregorian.ly"
<<
        \new Voice = foobar { f'( a' g' f') }
        \new Lyrics \lyricsto foobar \lyricmode { lalah }
>>

It breaks also with \addlyrics:

\include "gregorian.ly"
\new Voice = foobar { f'( a' g' f') }
\addlyrics { lalah }

cheers,
Janek