Strange behaviour when using -DFOREGROUND

Hi! I just installed Apache 2 on my Arch Linux Desktop machine for
testing purposes and instead of running it as a system wide service
through systemd I run it under my default user session whenever I need
it, using the following command:

/usr/bin/httpd -d "$HOME/Webserver" -f "$HOME/Webserver/httpd.conf"

Of course I did setup a working environment for it there.

Now I switched my configuration to use mpm_prefork and discovered a
strange behaviour which I do not understand: Whenever stopping a server
(by using -k stop or SIGTERM) started with -DFOREGROUND through a
.desktop starter, it not just kills the server and its children but my
whole desktop session, throwing me back to the display manager's login
screen. It does not happen when the commands are executed from a
terminal window.

Does anybody know why this happens? Is it a bug? It thought DFOREGROUND
should just keep it from detaching from terminal, therefore being a
harmless option.