vc, diff and scroll window

[Matthias]

Hi,

Suppose I have a buffer visiting a file which is under version
control, and say that that file as been changed and saved. When I
press C-xvu (calling vc-revert-buffer), the selected window get split,
a (curiously, unfontified) diff buffer is shown, and Emacs ask
`Discard changes' (the minibuffer is selected). 

Then M-C-v (scroll-other-window) doesn't work, so I can not scroll the
diff buffer!

Strange no? Is it a bug? What about the fontificationt problem?

I am using GNU Emacs 21.3.1. Thank you for your help.
-- 
Matthias