You need to run tce-update, as you are running the old Xprogs and Xlibs.
Ok, the issues reported on my posts in this thread seem to be related.
I investigated a bit, and this is my hypothesis: I upgraded from microcore 4.1 to core 4.2, and appsaudit (gui) returned no extension needed to be updated.
This turned out to be
wrong: manually downloading Xlibs, Xprogs, fluxbox, I checked they did need to be updated.
Probably (the old version of) appsaudit returns the message
Please standby... Now checking for your extensions.
Scan for updates completed.
only because the error given by the deprecation of /opt/.tce_dir is mishandled.
The problem is that one thus is caught in a vicious circle, which can be broken by either manually downloading Xlibs, Xprogs and fltk, or either by booting text base norestore, manually setting up a internet connection, and using tce-update /path/, which I did.
Anyway, I did not find a clear statement of this problem, which appears a bit subtle until one stumbles on it.
All this matter boils down to using tce-update instead of appsaudit, as Gerald hinted.