Bug???

[rsff]

Guys,

I think there's a bug.  I did this.

+++++++++ [ BEGIN ] +++++++++++++++++++++++++

[. . . ]

\score {
        \simultaneous {
                \context ChordNames \acordes
                \context Staff \musica
        }
        \paper {
                \translator {
                        \StaffContext
                                minimumVerticalExtent = #'(-4.0 . 0.0)
                }
                \translator {
                        \VoiceContext
                                Stem \set #'thickness = #2.0
                }
                \translator {
                        \ChordNamesContext
                                chordChanges = ##t
                                verticalExtent = #'(0.0 . 4.0)
                                ChordName \override #'style = #'american
                                ChordName \override #'font-magnification = 
#'1.25
                }
        }
}
++++++++[ END ] +++++++++++++++++++++++++++++

Lily responds like this. 

+++++++++++++ [ BEGIN ] +++++++++++++++++++++++++

/home/rsff/Documents/Musica/Composições/ChoroR.ly:169:13: error: parse error, 
unexpected SET, expecting OVERRIDE or REVERT or '=':
                                Stem \set
                                          #'thickness = #2.0

++++++++++++++++++++[ END ] +++++++++++++++++++++

So, Either the docs are wrong ( have the one ONLINE ). THey read that you can 
SET in the Translator score, or something is wrong with lily. . . I bet its 
the Manual that has not been updated. . . . . . 

Fabio.