RE: diff-mode

[Drew Adams]

> ediff is very interactive and it makes a lot of color noise, 
> moreover it opens another small frame which...
> I think is a bit buggy, since if I press "q" it doesn't 
> disappear but I have to close it manually.

M-x report-emacs-bug.  Typing `q' in the Ediff control buffer should always quit
Ediff (after you answer `y' to confirm).  If the Ediff control buffer is in its
own frame, then be sure that frame has the input focus when you type `q'.

If `q' doesn't work for you, please report it as a bug, providing a recipe that
starts with `emacs -Q'.

> As I discussed with a collegue, one of the problem of emacs are the
> non-inviting defaults. ...  But that's another topic...

Yes, it is.  And probably better for emacs-devel than for help-gnu-emacs.