I finally found out why the ez-page filter wasn't working. It turns out it was working just fine, as long as your language id in the database is 1. So if you delete the default (English) language from your ZC installation, and/or add a new language, and thus with a higher language id the filter will not show the pages.
I didn't know there was a language id in the table ezpages, and discovered it by accident after eliminating all the code differences between previous versions of ZC. The strange thing was that in my new "clean" multisite testshop the filter kept working in all ZC versions. Only after adding a second language, I saw that it didn't work for the new language. The language id in the table stays at 1 and is I think not used by default, other than that it is present in the ezpage table

Now the search starts for the best solution.
  • the first and easiest would be to deleted the language sensitivity (not my favourite)
  • the second is to integrate the ez-page filter module in to the ez-page multilingual module. (currently working on this one)