Bug 10747 – REGRESSION: Using two fingers on a trackpad to scroll inside a text area makes the whole page move

• Component: WebKit Misc.
• Status: RESOLVED FIXED

[Daniele Metilli]

If you try to use a scroll wheel inside a text area, you will see that the whole page moves together with it.

You can try this in the attached test case.

This happens in TOT (r16248), it doesn't happen in the latest stable version.

[Daniele Metilli]

Created attachment 10412 [details]
Test case

I can't see any difference in behaviour from latest release, neither in 16225 nor in 16259. Maybe the bug was introduced and fixed in between?

[Daniele Metilli]

I was wrong, it only happens with the two-fingers scrolling on my MacBook trackpad.

Scrolling with a Mighty Mouse scroll wheel works correctly.

It is still a regression, trackpad scrolling works in the stable version of Safari.

[Daniele Metilli]

Created attachment 10449 [details]
Test case

[Rachael Worthington (cheers)]

I can reproduce this with a normal mouse in the latest nightly, by copying and pasting a block of text, pasting it into the Additional Comments text area a few times till there is a scroll wheel, and then scrolling over it.

whether focus is in the text area or not, the whole window scrolls, and not the text area.

reproed in the latest nightly as of Oct 23rd (r17205)

[tim bates]

I can confirm this bug.

In Daniele's regression, you can't scroll the text box with two-finger scrolling.

In addition, you can't scroll the text box using the mouse either. the thumb does not move when you click and drag on it.

I find this happening on many other  pages as well

[Daniele Metilli]

The status of this bug should be changed to NEW.

[Matt Lilek]

This was fixed in r18253.

*** This bug has been marked as a duplicate of 11313 ***

[Daniele Metilli]

I'm re-opening this bug since it still happens in the latest nightly (r17865).

Please note that it only happens using two fingers on a trackpad, not using a scroll wheel.

[Daniele Metilli]

Oops, I meant 18765, not 17865.

[Daniele Metilli]

My test case still displays the problem. The one from bug 11313 works correctly.

I think this is because the page from 11313 can't be scrolled (it contains only the textarea).

Conversely, my test case contains some text below the textarea, so it shows the bug.

[Matt Lilek]

I can't reproduce this with my trackpad (nor my scrollwheel mouse fwiw), but I'm also using iScroll and not an officially supported scrollie trackpad so...that may or may not be the issue.

Can anyone else with an official trackpad confirm this?

[David Kilzer (:ddkilzer)]

Confirmed using a locally-built debug build of WebKit r18997 with Safari 2.0.4 (419.3) on Mac OS X 10.4.8 (8N1037) on a MacBook Pro Core 2 Duo.  Note that you must have the "Use two fingers to scroll" option enabled in the Keyboard & Mouse preference pane for the trackpad.

[Alexey Proskuryakov]

Regression -> P1

[Mark Rowe (bdash)]

<rdar://problem/5045710>

[Adele Peterson]

*** Bug 13024 has been marked as a duplicate of this bug. ***

[Antti Koivisto]

Trackpad is generating wheel NSEvents which have both deltaX and deltaY set to 0. These events are ignored by WebCore and so get forwarded to the view. There they actually make the NSScrollView scroll. I wonder what is the logic there... Mouse wheel does not generate these (0,0) events so does not have the same scrolling problems.

Trivial solution of just blocking (0,0) events seems to degrade speed and general feel of trackpad scrolling.

[Antti Koivisto]

weinig pointed to http://developer.apple.com/qa/qa2005/qa1453.html which might be relevant

[Antti Koivisto]

r20349

Also filed bug 13134, "Implement smooth scroll events"