Preview always assumes that you are going to print with the "records being browsed" option selected and thus previews the entire found set rather than just the current record. A common work around for this is to limit the found set to just the current record. Then the record previewed and the current record correspond with each other.
Point of fact, you don't get a "current record" in preview mode, just a current page--which might show several records or just part of one record.
But you can save as PDF and specify a page range to save just the current page. The "book control" in the status area or a special inserted bit of layout text can show the current page number.
Thank you very much PhilModJunk for your quick response!
Now I understand the point of view of FM developers and will live with it. Even, from an intuitive view, I would expect that current record will change in preview mode and formular view. ;-)