378606 - [FIX]Does not return to the scroll position in the page after reload

Status: RESOLVED FIXED

(Core :: General, defect, P1)

Description

[Ria Klaassen (not reading all bugmail)]

When I scroll down and click Reload on some sites it doesn't return to the position in the page but stays on top.

It happens with the following URL:
https://bugzilla.mozilla.org/buglist.cgi?query_format=advanced&short_desc_type=allwordssubstr&short_desc=&product=Core&product=Firefox&product=Toolkit&long_desc_type=substring&long_desc=&bug_file_loc_type=allwordssubstr&bug_file_loc=&status_whiteboard_type=allwordssubstr&status_whiteboard=&keywords_type=allwords&keywords=&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&resolution=EXPIRED&resolution=MOVED&resolution=---&emailassigned_to1=1&emailtype1=exact&email1=&emailassigned_to2=1&emailreporter2=1&emailqa_contact2=1&emailtype2=exact&email2=&bugidtype=include&bug_id=&votes=&chfieldfrom=-0d&chfieldto=Now&chfield=[Bug+creation]&chfieldvalue=&cmdtype=doit&order=Reuse+same+sort+as+last+time&field0-0-0=noop&type0-0-0=noop&value0-0-0=

And mostly, not always, with this URL: https://bugzilla.mozilla.org/buglist.cgi?product=Core&product=Firefox&product=Mozilla+Application+Suite&product=Thunderbird&product=Toolkit&bug_status=UNCONFIRMED,NEW,ASSIGNED,REOPENED,RESOLVED&chfield=%5BBug%20creation%5D&chfieldfrom=-24h

But never, until now, with http://www.nu.nl/

I found the following regression range for it:
http://bonsai.mozilla.org/cvsquery.cgi?module=PhoenixTinderbox&date=explicit&mindate=1177105080&maxdate=1177110119
where bug 84582 is the only checkin.

I'm afraid this is a vague bug. I repeated it a lot of times however before filing this bug.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Fix

Basically fallout from deferring InitialReflow, in this case to after we finish parsing the document altogether....

Note that the exact location of the RestoreRootScrollPosition() call in InitialReflow is not that important as long as it happens after we construct the root scrollframe.  I went with doing it once we finish all the reflowing, just because.

Comment 2

[Boris Zbarsky [:bzbarsky]]

I wonder how to go about testing this... basically, I'd need a page with a stylesheet that is guaranteed to take longer to load than the body of the page itself will take to load and parse, in order to reproduce this bug reliably.

Comment 3

[aja+bugzilla]

FWIW, this checkin seems to have at least temporarily fixed the problem for me.  I'd been noticing it frequently on mozillazine forum pages (e.g. the daily trunk build threads in particular).  

Comment 4

[Boris Zbarsky [:bzbarsky]]

Fix checked in yesterday.