bug#16196: 24.3.50; Disable ding when scrolling

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> I'm not opposed to such an option, but I'm not convinced that changing
>> the default behavior is a good idea: the general design of Emacs is that
>> we strive to make every command perform *something*, so when the user's
>> request ends up doing nothing, we signal an error to make it clear that
>> Emacs did obey the request.  Otherwise the lack of feedback can make the
>> user feel like Emacs is unresponsive.
> The main use case here is "flinging" with a trackpad.  In that case, Emacs
> already responds by scrolling up/down to the top/bottom.  It is after Emacs
> has hit top/bottom that the "extra" beeps occur.

But if you're at EOB and you scroll with the wheel to try and go "even
further", if Emacs doesn't (ding), then it does nothing: lack of feedback.

> If already at the top/bottom, the normal thing for OSX apps is to
> "bounce" a bit to show that the display is already at the top/bottom.  If at
> the top, the whole page is moved a bit downwards and then bounces back.
> This is not common in X, so not really appropriate for Emacs.

Right, instead we (ding).


        Stefan