872254 - Relative positioned element disappears when original position is vertically scrolled off the viewport

Status: RESOLVED FIXED

(Core :: Layout: Positioned, defect)

Description

[bz_zolc]

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:18.0) Gecko/20130119 Firefox/18.0
Build ID: 20130119203203

Steps to reproduce:

On this page: http://larvoltrials.com/ohm.html
There are headers inside DIVs with position:relative that have their top property changed via javascript to follow the viewport on one axis only.


Actual results:

In Firefox 21 (and still in Nightly 24.0a1), while scrolling vertically, these headers follow the viewport as expected, until the viewport is scrolled enough so that the original (pre-positioning) area is completely outside the viewport, then they disappear.
The Inspector tool still shows their boundaries as following the viewport, they just aren't visible.


Expected results:

The DIVs should continue to be visible regardless of vertical scroll position. (Worked in Firefox 18 and chrome/IE9)

Comment 1

[Alice0775 White]

The similar problem happens in Firefox4...17.
So it is difficult to determine regression window.

Fixed window(m-aurora)
Bad:
http://hg.mozilla.org/releases/mozilla-aurora/rev/fa9a4d400949
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/18.0 Firefox/18.0 ID:20121010042011
Fixed:
http://hg.mozilla.org/releases/mozilla-aurora/rev/e3f7fdf150a4
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:18.0) Gecko/18.0 Firefox/18.0 ID:20121011042010
Fized pushlog:
http://hg.mozilla.org/releases/mozilla-aurora/pushloghtml?fromchange=fa9a4d400949&tochange=e3f7fdf150a4

Fixed by
cf470cfd18ca	Ehsan Akhgari — Backout bug 157681 in order to fix bug 775350 on Aurora; a=lsblakk


Unfortunately, The patch of bug 775350 does not fix this problem in Firfox19 and later.

Comment 2

[Alice0775 White]

Correct
>>The similar problem happens in Firefox4...17.
The similar problem happens in Firefox4...17 (when they were still in m-c).

Comment 3

[mjh563]

I get a different regression range:

Last good nightly: 2012-06-06
First bad nightly: 2012-06-07

Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=6338a8988917&tochange=7e4c2abb9fc9

It appears to be caused by the number of rows in the table. If there are <= 20 rows, it works. If there are more than 20 rows, the bug happens.

Comment 4

[mjh563]

Attachment: testcase

The red div shouldn't disappear when the page is scrolled.

If you remove one of the empty rows, it works.

Comment 5

[Loic]

(In reply to mjh563 from comment #3)
> I get a different regression range:
> 
> Last good nightly: 2012-06-06
> First bad nightly: 2012-06-07
> 
> Pushlog:
> http://hg.mozilla.org/mozilla-central/
> pushloghtml?fromchange=6338a8988917&tochange=7e4c2abb9fc9
> 
> It appears to be caused by the number of rows in the table. If there are <=
> 20 rows, it works. If there are more than 20 rows, the bug happens.

Confirmed, it has regressed since FF16.

Comment 6

[Boris Zbarsky [:bzbarsky]]

The comment 3 range would be bug 157681.  The comment 1 range was for the problem being _fixed_ between 17 and 18, which was done by backing out bug 157681.

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

It looks to me like we're failing to update an overflow area somewhere, probably table-related since this seems to depend on tables.

Comment 8

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Ah, this bug is because the table row cursor isn't being invalidated when UpdateOverflow happens.

Comment 9

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

Interesting that no equivalent bug was reported for blocks.

Comment 10

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 750279 [details] [diff] [review]
fix

>+  virtual bool UpdateOverflow();

MOZ_OVERRIDE, please.

r=me

Comment 11

[Robert O'Callahan (:roc) (email my personal email if necessary)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/441d2b9cecb4

Comment 12

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/441d2b9cecb4