`scroll-up-command' still broken in 21.2 under AIX

I still have that very annoying scrolling misbehaviour in 21.2 that I reported a while ago: http://www.xemacs.org/list-archives/xemacs-beta/199911/msg00262.html Unfortunately, there has been almost no response and I haven't found any solution for this - `scroll-up' hasn't worked for me in any beta since 21.2.19 under AIX 4.3.2, although it's ok on Linux. I assume there aren't too many guys out there on AIX, but am I the only one seeing this? If no, perhaps there's really something broken; if yes, what am I doing wrong? (`scroll-down' works and neither configuring `--with-scrollbars=athena' nor '--with-scrollbars=no' helps here). Any hints? Markus