Post and Pages display only the latest one in backend

Hello,

Since the latest upgrade to WP 4.0 my backend Post and Pages only displays the latest ones, although the count of Published items is correct and they are also shown correctly in public pages.

Furthermore, the “screen options” dropdown at top screen does not drop down for those 2 items (pages and posts) but works fine with other items in backend.

Any clues?

Thanks.