[tex-k] Problem with "mf" online display in GNOME

[Igor Liferenko]

Hi all,

This example from MetaFont Book (page 31) does not work with online
display (run as "mf test.mf"):

    drawdot (35,70); showit;

I traced down the problem to GNOME. On MATE desktop everything works properly.
There is also a report that it works in MobaXterm (X-Server on Windows 10):

    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=862943#10

The problem is not in TeX Live (I tested on official TeX Live ISO),
because this example works everywhere except GNOME. Thus, the problem
is with GNOME. Can you please point me to the code in TeX Live which
interfaces with window system so that I could trace down the bug
myself?

Thanks,
Igor