View Changes In File failure

[Ron]

Dear,

I use  GNU Emacs 22.0.50.2 (i686-pc-linux-gnu, GTK+ Version 2.8.20)
compiled on 2006-08-29 from CVS. When I have some file opened, which I
already saved once before (don't know whether it matters), then make a
change, and then exit Emacs using C-x C-c, I get the question whether
I want to Save that file. I get the option to View Changes In File.
Clicking this option loads diff-mode behind the modeless window,
flashes the screen (due to a redraw), and then does nothing. The
expected behaviour of "View Changes In File", which would be to show
some buffer with the changes presumably, does not occur.

Ron