1432796 - Directionality of RTL tab title is not reliably respected

Status: NEW

(Firefox :: Tabbed Browser, defect, P3)

Description

[Jonathan Kew [:jfkthame]]

STR, using Nightly (60.0a1) on macOS:

1. Open a new browser window.
2. Paste the URL https://www.walla.co.il/ and press Return to load the site.

>>> note that the page title "וואלה!" in the tab is displayed LTR: it is left-aligned, and the exclamation point appears at the right-hand end of the text

3. Open a new tab.
4. Load the same URL https://www.walla.co.il/ in this tab.

>>> observe the same result.

5. Repeat steps 3-4, until the tabs begin to compress, and eventually scroll (around 10 tabs or so, depending on browser window size).

>>> observe that eventually, once the new tab being opened is compressed to its minimum width (or thereabouts), the page title appears RTL: right-aligned in the tab, with the exclamation point at the left-hand end.

6. Now click on one of the older tabs that has the LTR title, and press Reload.

>>> observe that the tab title switches to RTL

7. Close some of the tabs, so that the tab-bar no longer scrolls, and they begin to uncompress slightly.
8. Now click one of the LTR-title tabs, and press Reload.

>>> observe that the title remains LTR

9. Click one of the RTL-title tabs (which was loaded while the tabs were fully compressed), and press Reload.

>>> observe that the title remains RTL


Expected result:
In this test, all the tabs have exactly the same title; they should all be displayed with the same directionality (RTL) throughout the test.

Inspecting the tabs with the Browser Toolbox, it appears that all of them -- whichever way they are displayed -- have the expected labeldirection="rtl" attribute set. But it is not having the desired effect on rendering in all cases.

Comment 1

[Dão Gottwald [:dao]]

Has this regressed or was this flaky ever since bug 1357656 landed?

Comment 2

[Jonathan Kew [:jfkthame]]

Looks like it's been this way ever since bug 1357656 landed. The RTL support only works properly if the tabs are sufficiently compressed, and/or the page title is long (with a really long title, the RTL display will kick in even with a wide tab).

Comment 3

[Itiel]

I'm unable to reproduce the issue in Windows 10 x86.

Comment 4

[Jonathan Kew [:jfkthame]]

That's odd -- it reproduces for me on Win10/x64.

Does the tab title appear LTR or RTL (consistently) for you? (Is your system locale and/or Firefox localization already RTL?)

Comment 5

[Itiel]

(In reply to Jonathan Kew (:jfkthame) from comment #4)
> That's odd -- it reproduces for me on Win10/x64.
> 
> Does the tab title appear LTR or RTL (consistently) for you? (Is your system
> locale and/or Firefox localization already RTL?)

Yes to all 3 questions.

To verify, I just need to open a new Nightly window (even if one is already opened with lots of tabs) and have it with a single tab to reproduce?

Comment 6

[Jonathan Kew [:jfkthame]]

Yes, an existing window is irrelevant. With a single tab in a new window, the tab title appears LTR, but once there are enough tabs in the new window for them to scroll, it appears RTL.

This is with en-US Firefox on an en-US system; if you're running with an RTL locale, I guess that may well affect the behavior (such that the titles always appear correctly in RTL mode). You might need to reset your system and/or Firefox locales in order to reproduce the glitch.

Comment 7

[Itiel]

(In reply to Jonathan Kew (:jfkthame) from comment #6)
> Yes, an existing window is irrelevant. With a single tab in a new window,
> the tab title appears LTR, but once there are enough tabs in the new window
> for them to scroll, it appears RTL.
> 
> This is with en-US Firefox on an en-US system; if you're running with an RTL
> locale, I guess that may well affect the behavior (such that the titles
> always appear correctly in RTL mode). You might need to reset your system
> and/or Firefox locales in order to reproduce the glitch.

Nope, changing the intl.uidirection pref on about:config is enough to make it reproduce. I see it now here as well.
So the real issue here is that RTL is not respected when Firefox's UI is set to LTR.
And even if you open lots of tabs so the tab strip would overflow, hovering over the tab with the webpage from comment 0 displays the tooltip as LTR.

Comment 8

[Jonathan Kew [:jfkthame]]

(In reply to Itiel from comment #7)
> And even if you open lots of tabs so the tab strip would overflow, hovering
> over the tab with the webpage from comment 0 displays the tooltip as LTR.

The tooltip is a separate issue, part of bug 1169986 (which we should pick up again -- it has lingered too long!)