1274571 - Scroll position lost in bugzilla.mozilla.org

Status: RESOLVED INVALID

(Core :: Layout, defect)

Description

[blinky]

Steps to reproduce:

1. Log out of bugzilla account.
2. Go to https://bugzilla.mozilla.org/show_bug.cgi?id=1267720.
3. Go to the bottom of the page.
4. Go to the link in the last comment.
5. Click the back button in the browser.


Actual results:

Scroll position is lost.

See https://dl.dropboxusercontent.com/u/95157096/85f61cf7/83ru4rqsmd.mp4

Comment 1

[blinky]

Regression window:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=ceb2fd9beec76ec09fd89ba5d3dd736035877131&tochange=9489784a0ea049b149ad0c6d22ac121ef2542239

Suspect: bug 1269539 or bug 1268195

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Thanks, I'll look into it.

Comment 3

[blinky]

(In reply to blinky from comment #0)
> Steps to reproduce:
> 
> 4. Go to the link in the last comment.

It also occurs when reload page instead of going to the link.

Comment 4

[Kartikaya Gupta (email:[e-mail])]

Actually I don't think this is a bug. Chrome behaves the same way. The reason this happens is that when the page is loaded, the MozReview section near the top is not populated. After load, that section gets populated and pushes the rest of the content down. So even though we stay at the same scroll position, the content is shifting down under us, making it look like the scroll position changed. I would argue that this behaviour is correct, even though it is a "regression" from before, because this is what we do in general if the content shifts around after page load.

If we want to fix this, we should implement the scroll anchoring behaviour that Chrome is planning to implement [1].

[1] https://developers.google.com/web/updates/2016/04/scroll-anchoring