Maybe it was my mistake to mix, in the same title, two INDEPENDENT subjects: FLTK (GUI) and Xvesa (X server).
The MAIN point was to focus on small total RAM demand when we run few program in parallel.
It is NOT optimal to simultaneously run aterm (a FLTK terminal) , xmms (a GTK1 audio player), gnumeric (a GTK2 spreadsheet) and abiword (a GTK3 word processor). The point was that almost all programs to use the same GUI: FLTK, or GTK1, or GTK2.
For example, a minimal RAM demand combination run (under qmenu) if we focus on GTK2 was with Xvesa:
- gnumeric gtk2 1.10.17 (from tc 3.x), abiword gtk2 2.8.6 (from tc 4.x), vlc 2.2.1 qt4 (from tc 6.x), netsurf 2.8 gtk2, pacman etc
The next upper step, with GTK3 was:
- gnumeric gtk3 12..49 (from tc 12.x), abiword gtk 3.0 (from tc 12.x), vlc 3.0.11 qt5 (from tc 12.x), netsuft 3.10 GTK3 (from tc 12.x)
So if we try to lower the RAM demand (using FLTK or GTK1 only), then
- dillo 3.1 fltk, mplayer-no-dependency, fluff fltk 1.07, etc
But then we are without javascript, old programs with bugs (or obsolete format): can not navigate most web-sites, can not interchange docs with new M$Office 365 etc
Summary: is (next to) useless to gain few MB for X-sever (Xvesa, Xfb, Xorg) and then loose many MB for programs + all their not shared dependencies (different GUI kit).