1593840 - [RTL] In-content HTML page scrollbars are on the incorrect side

Status: NEW

(Core :: Layout: Scrolling and Overflow, defect, P3)

Description

[Itiel]

Attachment: Screenshot

This was an issue before, but bug 1525175 made it worse by extending the scrollbar to the entire view's height, and now it is more obstructive.

See attached.

Comment 1

[Mark Striemer [:mstriemer]]

So about:preferences manages to do this. It looks like it's from the localedir="rtl" property, but I can't get this to work in about:addons or about:config which are HTML documents. Going to need to dig into it a little more.

Comment 2

[Itiel]

btw bug 1514316 first regressed this.

Comment 3

[Mark Striemer [:mstriemer]]

STR

1. Set Firefox to RTL mode (`intl.l10n.pseudo = "bidi" should work)
2. Open about:config
3. Click the "Show All" button
4. Scroll

Expected Results: The scrollbar is on the left side.
Actual Results: The scrollbar is still on the right side.

This is also happening in the about:addons HTML frame (which should eventually move top-level but about:config is there now).

Bug 1594059 is similar for about:preferences (XUL) where the scrollbar is missing in some cases.

Comment 4

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

The priority flag is not set for this bug.
:dbaron, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

The pref's description and the code that implements it might be helpful here, although I don't see why any of that would lead to an HTML versus XUL difference, unless perhaps it's a parent process versus content process difference. (The two relevant prefs here are layout.scrollbar.side and bidi.direction.) I don't remember what the rules about preferences in the content process are...

The other question is whether the behavior here matches (a) web pages and (b) user interface generally.