weird behavior of ediff with multiple displays

[Evil Boris]

Has anyone seen the following beahavior from ediff while running on
multiple displays (not multiple screens of the same display):

While logged in remotely through SSH with X tunnelling turned on, I
execute (details: Solaris 2.7, :0.0 is local display, localhost:10.0
is SSH tunneled display):

emacs-cvs -Q -q --display :0.0 --eval '(make-frame-on-display "localhost:10.0")

Now in the resulting window that pops out on localhost:10.0 (remote
display) I execute "M-x ediff RET file1 RET file2".  What I get on the
localhost:10.0 display is the usual ediff control frame PLUS a weird
wide and narrow (one or two lines tall) *Minibuf-0* frame (a dedicated
minibuffer frame!?!?) that I definitely did not ask for.

I have seen this happen over many versions of CVS Emacs, with remote
machine being a WinXP box with an X server, or a Linux box (ancient
Mandrake, if it matters), so I am pretty sure it's an Emacs ediff
"feature".

Interestingly, if I start emacs-cvs by hand with localhost:10.0
display and then make-frame-on-display on :0.0, the effect
disappears---it seems to matter which display was opened first.

Any ideas would be welcome.  How do I debug this?  Can anyone
reproduce this?

          --Boris