> That was Motif but not CDE.

Indeed it's not CDE (although GP could just be saying that he liked old school WM / UIs like CDE, not necessarily that the one in TFV was CDE) but I think technically in the vid it's even SGI's 4Dwm. Heavily based on Motif but not totally visually identical to Motif? According to Wikipedia 4Dwm began in 1991.

As a sidenote a friend back then was lucky enough to have a SGI at home (for his stepfather was at the head of SGI Benelux) and that 4Dwm environment always struck me as particularly slick.