[plt-scheme] MrEd: multiple displays

Neil W. Van Dyke writes:
 > If your goal is to do "shared whiteboard" tutorials of MrEd apps like
 > DrScheme, I'd try something like XMX
 > ("http://www.cs.brown.edu/software/xmx/") or a multiple-display hack
 > based on VNC or RDesktop.
 > 
 > If you wanted to share non-GUI MzScheme app displays, you could use GNU
 > Emacs.  (At least one of the wearable computing people has done this for
 > demoing what he sees on his head-up display.)

Actually, it was the combination of VNC and XEmacs that made me want
to show a window on multiple displays.  I connect to my campus machine
from home via VNC, and I had a MrEd process running inside XEmacs that
was displaying to the VNC display (vega:1).  But today I came into
campus and logged into the console, connected to the XEmacs process
(via gnuclient), and wanted to get the still-running MrEd process to
display to the console (vega:0).  Instead I had to run vncviewer
locally to see it.  I suppose that was essentially the
"multiple-display hack" you were thinking of, but it seemed like
overkill.

I guess I'm naive about how X works-- don't you already have to give
it a display argument when you make a top-level window?  Why is it
that hard to expose this argument to the MrEd top-level window classes?

--dougo at ccs.neu.edu