1714720 - Cannot keyboard-scroll when focused element and scrollable element are separated by a process boundary

Status: NEW

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

Description

[Botond Ballo [:botond]]

Steps to reproduce

1. Load https://hsivonen.fi/fission-host.html, with Fission enabled
2. Click inside the first black box, thereby giving focus to content inside the OOP iframe
3. Press the down arrow key

Expected results

The enclosing document scrolls downwards. Note, this is what happens with Fission disabled.

Actual results

Nothing scrolls.

Comment 1

[Hiroyuki Ikezoe (:hiro)]

I hadn't noticed this at all for a long time.

Note that Chrome has the same behavior, it doesn't scroll.

Comment 2

[Chris Peterson [:cpeterson]]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #1)

Note that Chrome has the same behavior, it doesn't scroll.

Botond, do you think this bug should block shipping Fission?

Fission is causing a regression in Firefox's scrolling behavior (which is bad), but we now match Chrome's behavior (which might be good).

Comment 3

[Botond Ballo [:botond]]

My suggestion would be to not block shipping Fission, but consider it as a follow-up improvement instead. We can reconsider and increase the priority based on user feedback from the pre-release experiments (i.e. if users notice / report this change).

Comment 4

[Chris Peterson [:cpeterson]]

(In reply to Botond Ballo [:botond] from comment #3)

My suggestion would be to not block shipping Fission, but consider it as a follow-up improvement instead. We can reconsider and increase the priority based on user feedback from the pre-release experiments (i.e. if users notice / report this change).

Thanks. Move this bug to Fission's "Future" backlog.

btw, I tried bisecting this bug to see if it was a recent regression, but this keyboard scrolling behavior has been broken with Fission since at least Firefox 73 (January 2020). (I didn't bother testing builds older than that.)

Comment 5

[Botond Ballo [:botond]]

(In reply to Chris Peterson [:cpeterson] from comment #4)

btw, I tried bisecting this bug to see if it was a recent regression, but this keyboard scrolling behavior has been broken with Fission since at least Firefox 73 (January 2020). (I didn't bother testing builds older than that.)

Yep, that's what I would expect based on the code audit that led me to discover this in bug 1698693. We'd need a new IPC message to hand off the scroll to the enclosing document's process for this scenario to work with Fission.

Comment 6

[Chris Peterson [:cpeterson]]

Botond, in addition to keyboard scrolling not working in the OOP iframe, pinch zoom doesn't work when mousing over an OOP iframe. Does that change your assessment of whether this bug should be fixed for Fission MVP? Or should I file a new bug for the pinch zoom issue?

Comment 7

[Botond Ballo [:botond]]

(In reply to Chris Peterson [:cpeterson] from comment #6)

in addition to keyboard scrolling not working in the OOP iframe, pinch zoom doesn't work when mousing over an OOP iframe.

I believe that's an unrelated issue, and it's being fixed (with a fix to land soon) in bug 1700247.

Comment 8

[Chris Peterson [:cpeterson]]

(In reply to Botond Ballo [:botond] from comment #7)

(In reply to Chris Peterson [:cpeterson] from comment #6)

in addition to keyboard scrolling not working in the OOP iframe, pinch zoom doesn't work when mousing over an OOP iframe.

I believe that's an unrelated issue, and it's being fixed (with a fix to land soon) in bug 1700247.

Thanks. In that case, I will restore the Fission Milestone to "Future" so this bug doesn't block shipping Fission MVP.

Comment 9

[Hiroyuki Ikezoe (:hiro)]

Dropping Fission Milestone Future.

(In reply to Hiroyuki Ikezoe (:hiro) from comment #1)

Note that Chrome has the same behavior, it doesn't scroll.

Note that Chrome started handoff at some point, we will see a compat issue about this. I confirmed it on Chromium 96.0.4664.45.