Running Emacs (and possibly other applications) in a "Non Supported" Window Manager

[purgatori]

... will cause the system to freeze (at least it did on my system). The fix is simple, though.

Let's say you've installed the excellent Ratpoison window manager, and now you have the task of creating a desktop entry that GDM (and maybe KDM as well?) will understand. Ordinarily, all you would need is something like:

[Desktop Entry]
Type=Application
Version=1.3.3.7
Encoding=UTF-8
Name=Ratpoison
Comment=Minimalistic Window Manager

... in /usr/local/share/xsessions/16ratpoison.desktop

However, in order to avoid the crash, the following needs to be appended to the last line of the above file:

Exec=dbus-launch --exit-with-session ratpoison #Prevents Emacs from crashing

Hope this helps anyone else who encounters this problem.