Enhanced Motif Window Manager https://fastestcode.org/emwm.html
and the full-fledged CDE desktop that uses Motif also:
https://sourceforge.net/projects/cdesktopenv/ (note that you want to firewall this somehow as the default settings on the background process ttdb can be a security hole)
https://sourceforge.net/projects/motif/files/
https://en.wikipedia.org/wiki/Motif_%28software%29
(in some alternate universe, motif was under the x11 license and you would have motif v13 instead of GTK.)
Now we live in a time where we allocate GBs of RAM to eye candy that functionally accomplishes nothing. Then we make the case to rewrite the eye candy in increasingly "safe" languages, requiring even more RAM.
Well, of course it takes more ram when we run 4x the pixels for the same size screen. And we double the refresh rate, but then hold everything back a frame to composite it. :P
Which contrary to UNIX did not had the C mistake.
Rather Structured BASIC, Extended Pascal, COBOL, Modula-2, Fortran and Bliss.
It is really sloppy programming nowadays, regardless of the languages.