Re: [h-e-w] Help with scrolling - Emacs 22.3.1 windows

[David Vanderschel]

On Friday, November 07, "Jason Rumney" <address@hidden> wrote:
>David Vanderschel wrote:
>> On Friday, November 07, "Augusto Pedroza" <address@hidden> wrote:

>>> I can scroll down with the mouse "wheel" in the first
>>> windows only even when I have selected the second
>>> window.


>> I am running an older version of emacs, but I, too,
>> observe somewhat surprising behaviour with mouse-wheel
>> scrolling in the presence of horizontally split
>> windows.

>What does C-h k [mouse-wheel] report?

Actually, regarding the code that might cause a switch
of windows affected by the scroll wheel, I had already
mentioned:
>>It is not reflected in the higher level code
>>(w32-handle-scroll- bar-event) which ultimately
>>handles a given scrolling event.

which does provide the answer to Jason's question.

>Some mouse drivers do not simply send mouse-wheel
>events, but rather have their own (often buggy) code
>to locate the scroll bar and simulate scroll-bar
>events.

Indeed.  I have such a 'mouse' also - a GlidePoint
touchpad on my keyboard.  However, the behaviour I was
reporting was for a Dell USB mouse which is using the
standard Windows USB pointing device driver.  With
some effort, I was also able to get an apparently
'wrong' behaviour with the touchpad as well; but its
behaviour is different with a difference more like I
suppose that Jason was considering.

>If you do not use any special features of your mouse
>driver then you can try switching to one of the
>generic mouse drivers which will send proper wheel
>events.

No.  I like the way both drivers behave.  What
strangeness exists is not a problem for me.  I said
that.  My point was that the symptom I was observing
might well be the same as Augusto was observing and
that he was possibly misinterpreting the symptom and
its seriousness.  (Indeed, his statement of the
symptom was hardly clear to start with.)  I was able
to observe a (not very problematic) behaviour which
could conceivably be described in the same manner as
he described the behaviour which was concerning him.
In particular, I tried to emphasize that which window
is selected is not relevant with respect to which
window scrolls and that this behaviour is clearly
intentional based on looking at the code.  

(The routine I mentioned in the quote above saves the
selected window and restores it after messing with the
scroll position of whichever window is associated with
the mouse event.  Being time-delay dependent, it is
that _association_ which behaves somewhat strangely,
and the responsibility for the strangeness may well
lie outside Emacs.  However, I do see time-delay
dependence with both drivers.)

It is conceivable that Augusto has a mouse driver
which is behaving completely wrongly with respect to
guessing which scroll bar should be associated with
the mouse wheel at a given point in time.  If that is
the case, then Jason's suggestion to try a simpler
driver could potentially solve what may be a real
problem for Augusto - but not for me.  Indeed, it may
be that Jason thought he was responding to Augusto
when, in fact, he was replying to my response to
Augusto.

Regards,
  David V.