[Seaside] Nested Multi-Select-List.

[Philippe Marschall]

>                      callback: [ :r |   self creaScnCnt: html.  ]).
>
>                      callback: [ :r | self creaTrzCnt: html. )].
>

Doesn't work this way. You can't use the old renderer you have to use
the new one passed to you as a block argument.

Philippe