Programs like pcmanfm, evince, ... don't connect to dbus unless run with dbus-launch

[Brendan Tildesley]

Continuing on from my previous thread here:
https://lists.gnu.org/archive/html/help-guix/2017-11/msg00084.html

I discovered that I was able to work around the problem by running
pcmanfm with dbus-launch. Running `dbus-launch evince` also fixed an
issue I had with Evince not remembering the last page I was on in a
document. However, I understand next to nothing about dbus, gvfs, ,etc,
so I'm still not sure what the answer is. But I think this is the
essential clue that identifies the problem.

I tried modifying the slim service to launch the session with
dbus-launch, but that only served to create some new errors when running
pcmanfm:

-------

invoking IsSupported() failed for remote volume monitor with dbus name
org.gtk.vfs.UDisks2VolumeMonitor::
GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
org.gtk.vfs.UDisks2VolumeMonitor was not provided by any .service files
(g-dbus-error-quark, 2)
invoking IsSupported() failed for remote volume monitor with dbus name
org.gtk.vfs.GPhoto2VolumeMonitor::
GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
org.gtk.vfs.GPhoto2VolumeMonitor was not provided by any .service files
(g-dbus-error-quark, 2)
invoking IsSupported() failed for remote volume monitor with dbus name
org.gtk.vfs.MTPVolumeMonitor::
GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name
org.gtk.vfs.MTPVolumeMonitor was not provided by any .service files
(g-dbus-error-quark, 2)
-------

Although I can run `dbus-launch bash` from a terminal and then run
pcmanfm from there and it will work fine (no longer displays the hidden
mounts, and displays my actual hard drives, and lets me mount them). It
be great if someone could help solve this, I know at least a couple
other people in the irc chat have experienced this bug, usually when
using some tiling wm like i3 instead of the full GNOME desktop. Is it an
issue with SLiM, or and issue somewhere else?