Tab widget thingies can disappear when font-locking a buffer

The tab widget thingies go away in the following sequence: src/xemacs -vanilla C-x C-f lisp/startup.el M-x font-lock-fontify-buffer Hitting C-l makes them reappear. uname -a: SunOS miho 5.6 Generic_105181-05 sun4u sparc ../xemacs-21.2/configure '--with-mule' '--debug=no' '--error-checking=none' '--extra-verbose=no' '--site-prefixes=/usr/local' '--x-includes=/usr/local/X11R6/include' '--x-libraries=/usr/local/X11R6/lib' '--compiler=gcc' '--mail-locking=file' '--srcdir=../xemacs-21.2' '--cflags=-g -O3' '--with-xim=xlib' '--site-includes=/usr/lib/locale/ja/wnn/demo/include' '--site-libraries=/usr/lib/locale/ja/wnn/lib' '--with-widgets=athena3d' '--with-cde=no' '--with-tooltalk=no' '--with-scrollbars=athena3d' '--with-dialogs=athena3d' XEmacs 21.2-b22 "Mercedes" configured for `sparc-sun-solaris2.6'. Where should the build process find the source code? /usr/local/devel/xemacs-21.2 What installation prefix should install use? /usr/local What operating system and machine description files should XEmacs use? `s/sol2.h' and `m/sparc.h' What compiler should XEmacs be built with? gcc -g -O3 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 /usr/local/X11R6/include Where do we find X Windows libraries? /usr/dt/lib /usr/local/X11R6/lib Additional header files: /usr/lib/locale/ja/wnn/demo/include Additional libraries: /usr/lib/locale/ja/wnn/lib Additional prefixes: /usr/local Runtime library search path: /usr/lib/locale/ja/wnn/lib:/usr/local/lib:/usr/dt/lib:/usr/local/X11R6/lib:/usr/local/qt/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 TIFF image handling. Compiling in support for X-Face message headers. Compiling in support for Berkeley DB. Compiling in support for GNU DBM. Compiling in support for ncurses. Compiling in Mule (multi-lingual) support. Compiling in XIM (X11R5+ I18N input method) support. Using raw Xlib to provide XIM support. Compiling in support for Canna on Mule. Compiling in support for the WNN input method on Mule. Using WNN version 6. Compiling in support for proper WM_COMMAND handling. Using Lucid menubars. Using Athena-3d scrollbars. Using Athena-3d native widgets. Using Athena-3d dialog boxes. Compiling in DSO module support. movemail will use "dot-locking" for locking mail spool files.