Thanks for adding the code in the default file, luci.
Laetitia, you can get Tikipedia's version of this file here: tiki-show_page.tpl. Save it as a .tpl file and upload it to your site's templates/styles/tikipedia directory. I didn't test it yet, so please post again if there are any problems.
it must be changed in tikipedia theme's tpl file too (if it has one called tiki-show_page.tpl in templates/styles/tikipedia/)
Your changes haven't fixed it on my machine
Could depends on my tikiwiki installation?
I've tikiwiki 2.0 migrating from 1.9 and I'm using tikipedia theme.