stock 5.9 installation, gdm starts by default. attempt to run Xnest :1 -query localhost from an xterm results in blank Xnest. Same command on 5.2 brings Xnest with login prompt. according to the gdm config file, remote access is enabled. more clues: $ netstat -a | grep 177 udp 11152 0 *:177 *:* number '11152' is a queue length which increases with every Xnest attempt. looks like requests are igonored.
It works if debugging is enabled in /etc/X11/gdm/gdm.conf. However logout doesn't work.
*** This bug has been marked as a duplicate of 2594 ***