Comment 4 for bug 524761

@Julien Lavergne
I've been experimenting with lightweight installations built up from a command-line install. I have been using lxdm, xdm, qingy and sometimes no login manager.

I did some further experimentation, namely installing lxdm with no-recommends on an openbox-only install, and the same problem appeared. I've just found that qingy creates the same or a similar problem, so I've removed it. (I imagine, though, that this would be outside of your area of concern.)

So, essentially, the problem of /etc/environment not being read occurs when I have lxde-core/lxde-common or lxdm (or qingy) installed.