... "virtual" desktop.
Also: viewing other hosts as a virtual desktop is supported - by tabbing in between them. (X11 also supports each host runnign apps on the others' screen)
(* also from: uwm, twm, swm, X11, contributors, possibly mostly so)
notes: complicated m4 system feature is not currently working (linux) but automake configure makes the compile / install of this "classic Sun Site tarball" a breeze
$ sh ./configure --with-xpm --with-shape
$ make
$ make install