946632 - input field can scroll and scrollTop returns 0

Status: RESOLVED FIXED

(Core :: Layout: Form Controls, defect, P4)

Description

[sworddragon2]

Attachment: test.xhtml

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:25.0) Gecko/20100101 Firefox/25.0 (Beta/Release)
Build ID: 20131028112446

Steps to reproduce:

1. In the attachments is a testcase for this bug.
2. After opening it select the text in the input field and keep the left mouse button pressed.
3. Move down the mouse as you would to select another line.


Actual results:

1. The input field does scroll.
2. After the scrolling the scrollTop attribute returns 0.


Expected results:

As input fields have no onscroll attribute it is likely that they should never scroll. If the text is too big it should be simply hidden. But if we want to keep the scrolling behavior it should at least update the scrollTop attribute.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Input fields have to scroll, if you think about it: if the text is longer than the input field, it has to scroll to show it.

Comment 2

[Mats Palmgren (inactive)]

Both IE11 and Chrome33 supports vertical scrolling when doing selection-by-mouse.
Neither do mouse-wheel vertical scrolling though.
IE11 dispatches scroll events, Chrome does not, for both vert./hor. scrolls in both cases.
Chrome reports a non-zero scrollTop when scrolled, IE11 always reports zero.

(Nightly actually has a non-zero scrollTop after a vertical scroll, so that part of
"actual results" not true in Nightly.)

Since all three UAs supports vertical scrolling for selection-by-mouse I think
we should leave that as is.  I also think we should report the true (non-zero)
scrollTop in that case.  I also think we should continue to support scroll events,
for both vertical and horizontal scrolls, and have the HTML spec amended to support
that.

What we should change is: remove support for mouse-wheel vertical scroll (it should
scroll the nearest enclosing scroll view instead), for compatibility with IE/Chrome.

Boris, what do you think?

Comment 3

[Mats Palmgren (inactive)]

Attachment: Testcase #2

Comment 4

[Mats Palmgren (inactive)]

Boris, do you agree with comment 2?

Comment 5

[Boris Zbarsky [:bzbarsky]]

Comment 2 sounds perfectly reasonable to me.

Comment 6

[Mats Palmgren (inactive)]

Attachment: Don't scroll vertically by mouse-wheel on a single-line text control.

https://tbpl.mozilla.org/?tree=Try&rev=a31c0f137e34
https://tbpl.mozilla.org/?tree=Try&rev=10cb02d57314

Comment 7

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 8351043 [details] [diff] [review]
Don't scroll vertically by mouse-wheel on a single-line text control.

r=me

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2d6cee5b1223

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/2d6cee5b1223