1328052 - Scrollbar position doesn't update when page sets scrollTop after restoring scroll position

Status: NEW

(Core :: Layout, defect)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
STR_1:
1. Open http://stroi.mos.ru/
2. Open console (Ctrl+Shift+K), detach it to separate window
3. Scroll the page to the middle by dragging scrollbar thumb
4. Press Ctrl+R to reload the page, wait until it fully loads
5. Switch to console, execute "document.documentElement.scrollTop=0"


STR_2 (easiest):
1. Extract attached "testcase 1", into a folder with short full name, open .htm file in Firefox
2. Scroll the page to the middle by dragging scrollbar thumb
3. Press Ctrl+R to reload the page, wait until it fully loads
4. Click on the circle button at the bottom-right (it sets scrollTop)


STR_3:
1. Extract attached "testcase 1", into a folder with short full name, open .htm file in Firefox
 (the same steps as in STR_1)
2. Open console (Ctrl+Shift+K), detach it to separate window
3. Scroll the page to the middle by dragging scrollbar thumb
4. Press Ctrl+R to reload the page, wait until it fully loads
5. Switch to console, execute "document.documentElement.scrollTop=0"


AR:
 In penultimate step scroll position restores correctly.
 In last step the page scrolls to the top, but scrollbar thumb somehow stays on its place

ER:
 In last step scrollbar thumb should teleport to top of scrollbar, i.e. show actual scroll position


This is regression from bug 811301 (presumably). Regression range:
> http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=a761bfc192b5&tochange=58ebb638a7ea

Note:
 There's also bug 810470 in pushlog, but it was uplifted to Aurora 18. I tested 
 Aurora 18 (2012-11-19), and it's unaffected. Therefore this bug is most likely caused by bug 811301.@ Robert O'Callahan (:roc) (email my personal email if necessary):
It seems that this is a regresion caused by your change. Please have a look.

Comment 1

[arni2033]

@ Robert O'Callahan (:roc) (email my personal email if necessary):
It seems that this is a regresion caused by your change. Please have a look.

Comment 2

[arni2033]

Attachment: testcase 1 - bug 1328052.zip.001

Comment 3

[arni2033]

Attachment: testcase 1 - bug 1328052.zip.002

Comment 4

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

I don't work at Mozilla anymore.