Art: He is using startx, not xdm, it seems.

Hanspeter: xdm configs won't do you a bit of good.  However, like you
I forgot about xnest.  (^&


[Somewhat long tangential comment to follow.  Skim if you're not interested
 in the full blast...]

But, *most* window managers do not require their own X server.  I did
that for a "sandbox account" because of a bug (in my view) of one of GNOME
or KDE in the past, and I like to occasionally check up on those desktops
to see what they are doing.  All that you need is to have no more than one
window manager AT A TIME on your X server.

You may also have the same problem with xnest that you had with physically
seperate X servers.

The "bug" that I mention is that *some* (one of KDE or GNOME, at least
at one time in the past; plus a few window managers) applications will
kill the X server when they exit.  Although a window manager is a special
application, there should always be a way to exit the manager without
killing/crashing the X server.  Most window-managers are able to manage
this humble feat.

However, many people like to have their X server exit in response to
a window-manager menu, and an easy way to do *that* is to exec the
window manager as the final stage of your .xinitrc.  (I, instead,
run the window manager in the background and exec an xterm instead.
Then when I want to log out my X session, I exit the xterm.  I did
this initially so that I could swap window managers easily.)

Because a number of people set up their .xinitrc so that the window manager
is exec'ed when they run "startx", some menu configs for window managers
have the wm exit function (at least in default/standard configs) labeled
"logout".  Then some window managers take it a step further: When you
"logout", they not only exit, but kill your X server.  (Why they bother
isn't clear; if you wanted "exit window manager" to imply "exit X", you
would have set up your .xinitrc accordingly.  If you didn't set that up
in .xinitrc, you probably didn't want it to happen, regardless of what
the window manager's author decided to label the exit function in the
standard menus.)  Of course, this is only a "logout" if exiting X
implies logging out; those of us who run X from "startx" are just
annoyed that our X session died when we exited the window manager; we're
still logged in (thankfully), but have been kicked back to our text
console.

(mutter)

Okay. that's my personal rant.  (^&

I am not entirely sure why the system seems to have troubles when you
start more X servers.  I've observed this myself, but am unable to
pin down why.  I know that it never gave me such problems "in the
old days", and it may be related to XFree86 v4.x...  I know that I
*have* sometimes seen console output appear in the xcons window.
(Alright, that's what it's normally there for.  But I don't think
that it's appropriate to see login prompts appear there!  *grin*
But I have seen that kind of thing, which I never used to see.  I
have no clear path to replicating that, though it appears to involve
running multiple X servers, possibly only when xconsole is used, under
NetBSD/i386 v1.6, XFree86 v4.x.)


-- 
  "I probably don't know what I'm talking about."  http://www.olib.org/~rkr/