On Linux, why does the bitmap snapshot icon fail with a GLX error message?

Answer:

On some recent Linux distributions, the AUI Bitmap Snapshot command:

File > Bitmap Snapshot

or the Bitmap Snapshot icon

fails with a message similar to

Cannot create GLX Context

The issue is caused when the Linux server does not allow Indirect GLX. For general information about the issue, see the web pages

https://www.centos.org/forums/viewtopic.php?t=57409
https://www.hoffman2.idre.ucla.edu/access/x11_forwarding/
https://www.phoronix.com/scan.php?page=news_item&px=Xorg-IGLX-Potential-Bye-Bye
https://elrepo.org/bugs/view.php?id=610

Apparently, Indirect GLX poses a security issue, so Indirect GLX is now turned off by default.

This issue can be resolved by reconfiguring the Linux server to allow Indirect GLX, as discussed in the above web pages.

Unfortunately the resolution seems to be operating system and window manager dependent.

On Red Hat 7, the following solution appears to work:

1) Log in as root

2) Navigate to the /usr/bin directory

cd /usr/bin

3) Rename the file "Xorg" as "Xorg.original"

mv Xorg Xorg.original

4) Create a file "Xorg" with the following contents:

#!/usr/bin/env bash
exec /usr/bin/Xorg.original "$@" +iglx

5) Change permissions for "Xorg" using the commands

chmod +x Xorg
chcon --type=bin_t Xorg

6) Reboot