Hi Ernest!
thanks again! It almost works, however the pages with the unselected categories (in the WordPress backend) still show up together with the pages that have a category selected even if the two checkboxes are unchecked in the Frontend (the logic should be that with both checkboxes unchecked in the Frontend only the pages that have no selected category in the Backend show up for the user; if a user changes his mind and selects a category in the Frontend than only the pages with the category selected in the WordPress backend should show up)
Regards, Mario