in 2.5.8 connecting arpeggioBracket not works as in 1.6 version

[Albert]

The code:
\context PianoStaff <<
       \set PianoStaff.connectArpeggios = ##t
       \new Staff { \arpeggioBracket <c' e g c>\arpeggio }
       \new Staff { \arpeggioBracket \clef bass <c,, e g>\arpeggio }
     >>

and the code

\context PianoStaff <<
       \set PianoStaff.connectArpeggios = ##t
       \new Staff {  <c' e g c>\arpeggio }
       \new Staff {  \clef bass <c,, e g>\arpeggio }
     >>

give the same result -- connected arpeggios.
In version 1.6 it was possible to connect arpeggioBrackets, see: 
 http://www.lilypond.org/doc/v1.6/Documentation/user/out-
www/lilypond/Arpeggio.html

Albert