rest collision

[fiëé visuëlle]

Ahoi,
please consider this snippet:

\context Staff = StOne <<
        \time 3/4
        \context Voice = "main" {
                \relative c' {
                        e4 r e
                }
        }
        \context Voice = "secondary" {
                \relative c' {
                        \override NoteHead #'font-size = #-3
                        \stemDown
                        s e s
                }
        }
>>

The rest of voice "main" is placed below voice "secondary"'s note stem  
- why, since there's enough space above? And how can I avoid that?


Greetlings from Lake Constance
---
fiëé visuëlle
Henning Hraban Ramm
http://www.fiee.net
http://angerweit.tikon.ch/lieder/
https://www.cacert.org (I'm an assurer)