Dear Maintainers,
cgx has some issue with the freeglut version. There are already very old
bugreports like https://bugzilla.redhat.com/show_bug.cgi?id=1017551 which
illustrate the problem.
It is possible to downgrade to a very old version of freeglut, but that would
mean to install a version from 2012.
For example by downgrading to this version here:
https://snapshot.debian.org/archive/debian/20120714T033241Z/pool/main/f/freeglut/freeglut3_2.6.0-4_amd64.deb
I confirmed that it still works, downgrading indeed fixes the problem.

The problem can be triggered as follows:
$ cd /tmp
$ cp /usr/share/doc/calculix-cgx-examples/examples/result.frd.gz .
$ gunzip result.frd.gz
$ cgx result.frd

Left click, select Datasets -> 1 DISP
Crash:
freeglut (cgx): Menu manipulation not allowed while menus in use.

Best regards,
Sebastian

Hi

I can't reproduce the crash with 2.21 and 2.23, closing the bug
therefore.
It can be reopened, if the bug is still there.