246546 - OS X: scrollwheel scrolls webpages by an increasing amount of lines the longer you scroll

Status: RESOLVED INVALID

(Core Graveyard :: GFX: Mac, defect)

Description

[yatsu]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7) Gecko/20040608 Firefox/0.8.0+
Build Identifier: 12/06/04 Firefox nightly from nightly/latest-0.9 

Let's say one short movement of the scrollwheel should scroll 2 lines on a
webpage. What happens is that the first movement scrolls 2 lines, the second 4,
the third 6 and so on..

In other words while you are scrolling with the scrollwheel the amount of lines
you scroll with the same amount of movement increases dramatically - kind of
like the mouse accelleration feature found in most OSen, only now with the
scrollwheel.

Note that Camino and Thunderbird have this problem aswell, while Safari (a
native OS X app) does not.

Reproducible: Always
Steps to Reproduce:
1. Open the browser
2. Scroll a webpage using the scrollwheel

Actual Results:  
Amount of lines scrolled with a certain amount of movement increases while you
are  using the scrollwheel.

Expected Results:  
Consistently scroll an X amount of lines.

Comment 1

[yatsu]

Correction:

After scrolling once or twice using the scrollwheel, all following 'scrolls'
will scroll ~2 times as many lines.

Comment 2

[timeless]

smfr: i'm sticking this bug and any other like it into a mac filed category.
until the other thing gets equivalent, i will continue to do so.

Comment 3

[Simon Fraser [no longer active]]

Is this more than scroll events accumulating because scrolling is slow?

Comment 4

[Josh Aas]

This is an intended OS thing. If you scroll slowly, you'll get the standard 1-2
lines. If you scroll quickly you scroll more lines per "click" of the wheel (by
click I mean you should hear or feel the scroll wheel click).

In Safari, go to a long page in lxr and scroll so that line number 10 is at very
the top of the page. Scroll down 5 clicks, with 2 seconds between each click.
Note what line number you are on. Go back to having line 10 on top of the page.
Now scroll down 5 clicks, but quickly and in one smooth motion. Notice that
you'll end up on a much higher line number than before.

I tested this in Camino, Safari, Firefox, and all of my findings are consistent
with what I wrote above. I'm using a logitech USB wheel mouse on Mac OS X 10.4.2
with no special mouse setup.

Closing this as invalid.