That's it!  This has never been a critical issue so I never investigated it but I've always been curious why headers disappear despite having "Keep header visible while scrolling" checked.  I saw the article and had to look at it.  Great screenshots and thanks for getting right to the point.  Because it was so clear, I went right into an existing report, tried your settings and for the first time since I've been using SSRS my headers are staying in place.  Thanks for sharing!