gpm and X11 with psaux mouse - problem solved
I had the "glourious" idea to have at the look at the bug reports and
indeed found a helpful hint.
Somebody reported, that he solved the problem in
a) changing in /etc/X11/XFConfig86 the section Pointer back to
and b) in downgrading gpm (deinstall new gpm and reinstall old gpm of
slink) to version 1.14.
He wrote that it is important to do it in this chronological order to be
successful. This was presumably not the intention of the gpm maintainer
when updating to the new version 1.17.8, but it helped me.
The device line was inserted by cut and paste under X11. :-)