It looks like Xorg server ignores SIGTERM. At least it doesn't die when I invoke kill -TERM <pid> from the command line.
Also I've found that Xorg server dies upon receiption of SIGQUIT and SIGUSR2. Sending either of theese signals solves issue with hangup of ``systemctl stop xdm.service`` but doesn't solve issue with VT switching. Hope, this info will help you. BTW, LXDM also have same issue with DM stopping [as for me]. -- С уважением, Дунаев Антон. mailto: duan...@gmail.com