Description of Problem:
When I log in remotely to my machine (via ssh)
where evolution is already running with a window
open on the local X display (localhost:0) and
then I run evolution again it opens another window
on the local X display rather than the remote X
display (localhost:10).

If I kill evolution and restart it, it respects
the $DISPLAY variable and displays on the remote X
display.

So the problem here is that the first instance was
started with $DISPLAY=localhost:0 and when I start
the second instance from a remote login
($DISPLAY=localhost:10) it contacts the existing
instance of evolution and gets it to open the new
window. However, the old instance of evolution was
invoked with a different value of $DISPLAY so it
gets displayed on the wrong screen.

My guess at a fix would be that the protcol that
evolution uses to contact existing instances of
itself should be extended to pass the value of the
$DISPLAY variable and then the new window should
opened using that X display.

Steps to reproduce the problem:
1. start evolution on pc1 (DISPLAY=localhost:0)
2. login to pc1 from pc2 (ssh with X forwarding)
3. start evolution in context of remote login
session (DISPLAY=localhost:10)

Actual Results:
new evolution window (eg when invoked with a
mailto: link) is displayed on the local display of
pc1 (DISPLAY=localhost:0)

Expected Results:
new evolution window should open on local display
of pc2 (DISPLAY=localhost:10)

How often does this happen? 
always

Additional Information:
of course if you shutdown evolution and restart in
the context of the remote login session then
evolution respects the DISPLAY variable and
displays on the appropriate screen