1167911 - <object> in 'direction: ltr' when its embedded document's 'direction' is 'rtl' creates horizontal and vertical scrollbars

Status: REOPENED

(Core :: Layout, defect)

Description

[Gérard Talbot]

This spun from bug 1079151 comment #4 .

Initial conditions wrt OS settings
----------------------------------
Scrollbar width should be 18px or higher; scrollbar width is settable in Windows XP and in Linux KDE 4.13.3

Tests
-----

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/s71-abs-pos-non-replaced-icb-vrl-020.xht

and

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/s71-abs-pos-non-replaced-icb-vlr-021.xht

Actual results in Firefox 41.0a1 buildID=20150513191426
-------------------------------------------------------
The <object> will unexpectedly create horizontal and vertical scrollbars

Expected results
----------------
The <object> should *not* create horizontal and vertical scrollbars.

Notes
-----
- When scrollbar is set at 16px in Windows XP or at 15px in KDE 4.13.3, then no scrollbar is generated in the tests.
- The provided tests are not reduced, not minimized testcases: creating reduced tests should be doable, I believe
- I think the scrollbars generated have nothing to do with writing-modes
- I've set severity to minor since this is likely not a frequent issue and there is no dataloss or loss of functionality; just a minor layout issue
- I've set Component: Layout for further triage and test minimization
- I've searched for duplicates and did not find any

Comment 1

[Gérard Talbot]

What I see so far with Inspector tool is:

The <object> creates an horizontal scrollbar because the <div> in embedded document has its left offset computed to *minus* 4.4px. Such horizontal scrollbar reduces the viewport height of the <object> to less than 116px (116px minus width of scrollbar == 98px if the scrollbar width is 18px)... therefore creating a vertical scrollbar so that the vertical dimension of whole green square can be reached.

Where does such -4.4px come from? I have no idea.

Comment 2

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Per https://wpt.fyi/results/css/css-writing-modes?label=master&label=experimental&aligned&q=abs-pos-non-replaced-icb, both abs-pos-non-replaced-icb-vrl-020.xht and abs-pos-non-replaced-icb-vlr-021.xht are pass. I think we can close this bug.

Comment 3

[Gérard Talbot]

Ting-Yu Lin,
I wish we could reopen this bug report.

I can still reproduce the actual results with Firefox 68.5.0 ESR under Linux Debian 10.3 (KDE 5.14.5). I can upload a screen shot. I can do more tests too.
With Chromium 79.0.3945.130 and when setting scrollbars width to 25px (using an extension like Stylus 1.5.7), scrollbars are not generated in abs-pos-non-replaced-icb-vrl-020.xht and abs-pos-non-replaced-icb-vlr-021.xht .

I am happy that Firefox passes those tests over at wpt.fyi but that is not what this bug report is about.
This bug report 1167911 may be a unknown side effect / unexpected consequence of another bug report: I am thinking here of bug 764076 .

Comment 4

[Gérard Talbot]

I can reproduce the actual results with scrollbar width set to 17px and set to 16px in both Firefox 68.5.0 ESR and in Firefox 75.0a1 buildID=20200219095352 . In my opinion, there is something not okay, not appropriate here. A scrollbar width set to 16px is definitely not an extreme value, not an oversized scrollbar width.

I will do some more tests...

REOPENING

Comment 5

[Gérard Talbot]

Scrollbars are generated in both s71-abs-pos-non-replaced-icb-vrl-020.xht and in s71-abs-pos-non-replaced-icb-vlr-021.xht if scrollbar width is set to 15px in Firefox 68.5.0 ESR .

Scrollbars are generated in only s71-abs-pos-non-replaced-icb-vrl-020.xht if scrollbar width is set to 14px in Firefox 68.5.0 ESR.
Scrollbars are generated in both s71-abs-pos-non-replaced-icb-vrl-020.xht and in s71-abs-pos-non-replaced-icb-vlr-021.xht if scrollbar width is set to 14px in Firefox 75.0a1 buildID=20200221095110.

There is definitely a layout issue here: a 14px scrollbar width is moderate value if not a small value.

This is the content of my ~/.config/gtk-3.0/gtk.css file while testing:

scrollbar slider { background-color: gray; border-radius: 0px; }
scrollbar.vertical slider { min-width: 14px; min-height: 14px; }
scrollbar.horizontal slider { min-height: 14px; min-width: 14px; }

I can upload screen shots if asked to.

Comment 6

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Oops, I read this bug report too quickly. Thanks for reopening this.

I can upload screen shots if asked to.

It would be great if you could upload some screenshots to visualize the bug.

Comment 7

[Gérard Talbot]

Attachment: Screen shot of Firefox 75.0a1 buildID=20200221095110

The screen shot of s71-abs-pos-non-replaced-icb-vrl-020.xht is
with the following configuration of my gtk.css which is:

scrollbar slider { background-color: gray; border-radius: 0px; }
scrollbar.vertical slider { min-width: 14px; min-height: 14px; }
scrollbar.horizontal slider { min-height: 14px; min-width: 14px; }

Comment 8

[Gérard Talbot]

I did not upload a screen shot of s71-abs-pos-non-replaced-icb-vlr-021.xht because it is identical to attachment 9128320 [details] [diff] [review].
In the screen shot, we can see that there seems to be a 2px padding or spacing between the slider thumb and the scrollbar container... I think this has nothing to do with the issue involved here.

Comment 9

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Thank you for the screenshot!