1687189 - too early collapse of toggle containers

Status: NEW

(Core :: Layout, defect)

Description

[erik.christensen]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:84.0) Gecko/20100101 Firefox/84.0

Steps to reproduce:

If I load my website: ECstep.com (the homepage of my site) and click the cholesterol picture or the trans fat picture, you should go to: https://ecstep.com/fat/#cholesterol or https://ecstep.com/fat/#trans%20fats. respectively, but instead you go to the bottom of the https://ecstep.com/fat/ page after a temporary glimpse of the right position on the page. However, if you click the fatty acids picture on the homepage you are transferred to the correct place: https://ecstep.com/fat/#fatty%20acids and stay there.

I have tried Google Chrome and Microsoft Edge and these browsers do not produce the same problem. For that reason, I think the problem lies in Firefox and not in my website code.

Actual results:

See above.

Expected results:

10.01.2021 23.54 scher2000 responded as follows:
Hi Erik, this problem is related to the toggle containers. When the document loads, the toggle containers are fully expanded, then a script collapses them later. But in between, Firefox has already calculated the vertical numerical position for the internal link you went to, and it does not recalculate the position after the upper part of the page is drastically shortened. Of course, this is only a problem for the links that are below the toggle containers.

11.01.2021 01.34 I replied as follows:
Thanks for the reply.
I am certainly not an expert on toggle containers, but it seems to me that Firefox calculates the vertical numerical position for the internal link prematurely, i.e. before the upper part of the page is shortened and the length of the page to be displayed is known
The vertical numerical position should probably be calculated after the length of the page to be displayed is known. I hope this gives some meaning.

11.01.2021 10.03 jscher2000 responded as follows:
Hi Erik, you can file a bug report here and see whether Firefox can be changed later this year: https://bugzilla.mozilla.org/

Accordingly, I now submit this as a bug report to Bugzilla.
Best regards,
Erik Christensen

Comment 1

[Daniel Bodea [:danibodea]]

I confirm this issue on Windows 10 and Mac OS 11.1. This is an old regression. The regression investigation using mozregression could not be completed due to builds being too old (not found) and this is the most relevant result found:

2021-01-22T17:10:36: INFO : Narrowed nightly regression window from [2017-01-20, 2017-01-23] (3 days) to [2017-01-22, 2017-01-23] (1 days) (~0 steps left)
...skipped builds...
2021-01-22T17:14:04: INFO : Stopped

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Do you happen to know which code and at which time does it hide the "toggle containers"?

Firefox will try to scroll to the anchor twice, on DOMContentLoaded, and on load. Edge and Chrome are effectively the same browser (they use the same engine), and Safari behaves like Firefox here.

Comment 3

[BugBot [:suhaib / :marco/ :calixte]]

Clear a needinfo that is pending on an inactive user.

Inactive users most likely will not respond; if the missing information is essential and cannot be collected another way, the bug maybe should be closed as INCOMPLETE.

For more information, please visit BugBot documentation.