simplelist type="vert" causes FO error in 1.76.0

Hi,
 
It seems like something has changed for simplelist between stylesheet versions 1.75.1 and 1.76.0. I had no FOP errors prior to upgrading the stylesheets. When the type attribute of simplelist is inline or horiz, I get no error, but when type is vert I get the following from FOP (0.95):

 
ERROR - Ignoring property :column-width="proportional-column-width(1)" (file:[...] proportional-column-width() function may only be used when fo:table has table-layout="fixed" [...])
 

How can I fix this locally in the stylesheets to hide this error from our users?
 
Best regards,
Bergfrid Skaara