[BUG] `scroll-up' command broken in 21.2-b20 (AIX 4.3.2)

--text follows this line-- This bug report will be sent to the XEmacs Development Team, not to your local site managers!! Please write in English, because the XEmacs maintainers do not have translators to read other languages for them. In XEmacs 21.2 (beta20) "Yoko" [Lucid] (rs6000-ibm-aix4.3.2.0) of Wed Nov 10 1999 on pdw22.boeblingen.de.ibm.com configured using `configure rs6000-ibm-aix4.3.2.0 --site-includes=/afs/bb/rs_aix43/usr/local/include --site-libraries=/afs/bb/rs_aix43/usr/local/lib --compiler=cc '--cflags=-O -qmaxmem=-1 -I/usr/include/Motif1.2 /usr/lpp/X11/lib/R6/Motif1.2/Xm12.imp /usr/lpp/X11/lib/R6/Motif1.2/Mrm12.imp' --debug=no --error-checking=none --prefix=/afs/bb/u/altmark/rs_aix43/xemacs --with-jpeg' Please describe exactly what actions triggered the bug and the precise symptoms of the bug: Actions: 1. Started Xemacs: xemacs -vanilla & 2. Load any file, e.g. ~/.Xdefaults 3. Press the <Page Down> key (i.e. `next') which runs `scroll-up-command' or issue `M-x scroll-up RET' 4. The text does not scroll. Notes: 1. Jumping to the end of the buffer using `C-end' or `M-x end-of-buffer' works. 2. Scrolling down (e.g. from the end of the buffer) pressing the <Page Up> key or via `M-x scroll-down RET is ok. 3. Scrolling up and down dragging the scrollbar's slider also works, but if I click on the area of the scrollbar *below* the slider, the slider does not move down (and does not scroll the text). Clicking above the slider (e.g. when at the end of the buffer) works as expected. 4. As far as I can remember, I had the same effect with 21.2-b19 "Sneaky Bastard 19991102" a few days ago, but that one and b20 should be quite similar, right? Output of `M-x describe-installation': uname -a: AIX pdw22 3 4 009621754C00 ./configure 'rs6000-ibm-aix4.3.2.0' '--site-includes=/afs/bb/rs_aix43/usr/local/include' '--site-libraries=/afs/bb/rs_aix43/usr/local/lib' '--compiler=cc' '--cflags=-O -qmaxmem=-1 -I/usr/include/Motif1.2 /usr/lpp/X11/lib/R6/Motif1.2/Xm12.imp /usr/lpp/X11/lib/R6/Motif1.2/Mrm12.imp' '--debug=no' '--error-checking=none' '--prefix=/afs/bb/u/altmark/rs_aix43/xemacs' '--with-jpeg' XEmacs 21.2-b20 "Yoko" configured for `rs6000-ibm-aix4.3.2.0'. Where should the build process find the source code? /afs/bb/u/altmark/tools/xemacs/xemacs-21.2/build/xemacs What installation prefix should install use? /afs/bb/u/altmark/rs_aix43/xemacs What operating system and machine description files should XEmacs use? `s/aix4-2.h' and `m/ibmrs6000.h' What compiler should XEmacs be built with? cc_r -O -qmaxmem=-1 -I/usr/include/Motif1.2 /usr/lpp/X11/lib/R6/Motif1.2/Xm12.imp /usr/lpp/X11/lib/R6/Motif1.2/Mrm12.imp Should XEmacs use the GNU version of malloc? yes Should XEmacs use the relocating allocator for buffers? yes What window system should XEmacs use? x11 Where do we find X Windows header files? /usr/dt/include Where do we find X Windows libraries? /usr/dt/lib Additional header files: /afs/bb/rs_aix43/usr/local/include Additional libraries: /afs/bb/rs_aix43/usr/local/lib Compiling in support for XAUTH. Compiling in support for XPM images. Compiling in support for PNG image handling. Compiling in support for (builtin) GIF image handling. Compiling in support for JPEG image handling. Compiling in support for DBM. Compiling in support for CDE. Compiling in support for ToolTalk. Compiling in EXPERIMENTAL support for Drag'n'Drop ( CDE ). Compiling in support for proper WM_COMMAND handling. Using Lucid menubars. Using Lucid scrollbars. Using Motif native widgets. Using Motif dialog boxes. *WARNING* The Motif dialog boxes cause problems on AIX 4.3 and higher. We recommend using the Athena dialog boxes instead. Install libXaw and re-run configure with --with-dialogs='athena'. Read the PROBLEMS file for more information. movemail will use "lockf" for locking mail spool files. Recent keystrokes: C-x C-f . X d e f a u l t s RET next ESC x s c r o l l - u p RET misc-user Recent messages (most recent first): Parsing /afs/bb/u/altmark/.mailrc... Loading mail-abbrevs...done Loading mail-abbrevs... Loading emacsbug...done Loading emacsbug... Loading xrdb-mode...done Loading xrdb-mode... Loading efs-cu...done Loading efs-cu... --- Markus Alt IBM Laboratory Boeblingen, Germany