1173910 - Panning horizontally on MacOS X is janky/difficult when e10s is enabled

Status: RESOLVED DUPLICATE of bug 863514

(Firefox :: General, defect)

Description

[William Lachance (:wlach)]

Load this page in Chrome and Firefox:

https://wiki.mozilla.org/Buildbot/Talos/Running#Running_Tp_the_Automation_Way

Try scrolling horizontally using the Mac trackpad. On Chrome, it smoothly pans to the right. On Firefox, the scrollbar appears but there is no horizontal movement most of the time. After a few tries, you might see it move, but it's very inconsistent.

Comment 1

[William Lachance (:wlach)]

Incidentally, we fixed it another way, but this was a large reason for the initial complaint behind bug 1163083. I'm sure this causes problems all over the place.

Comment 2

[William Lachance (:wlach)]

Hi Steven, do you have any idea what might be happening here? I can't imagine I'm the first person who has noticed this.

Comment 3

[Steven Michaud [:smichaud] (Retired)]

I'll try your testcase, but first I need more information:

1) What version(s) of OS X have you tested on?
2) With what version(s) of Firefox?
3) Please give a detailed, precise description of what you think is going wrong.  No movies, no screenshots -- just a decent description.

By the way, bug 1163083 is *not* a performance bug.  Instead it's a bug in how Firefox interprets a horizontal swipe -- under some circumstances it mistakenly interprets it to mean "go backwards or forwards in history" (instead of "scroll the frame left or right which the mouse is over").  If that's what's going on here, this bug is presumably just as dup of bug 1163083 (though with perhaps a better testcase).

Comment 4

[Steven Michaud [:smichaud] (Retired)]

Oops, sorry.  What I said about bug 1163083 was incorrect.  I was thinking of a different bug.  But please do still answer the following questions:

1) What version(s) of OS X have you tested on?
2) With what version(s) of Firefox?
3) Please give a detailed, precise description of what you think is going wrong.  No movies, no screenshots -- just a decent description.

Comment 5

[William Lachance (:wlach)]

(In reply to Steven Michaud [:smichaud] from comment #4)
> Oops, sorry.  What I said about bug 1163083 was incorrect.  I was thinking
> of a different bug.  But please do still answer the following questions:

What was the other bug that you were thinking of? Maybe the misinterpretation of the swipe is the problem here.

> 1) What version(s) of OS X have you tested on?

Just 10.10.2

> 2) With what version(s) of Firefox?

via mozregression: nightlies from: 2015-06-10, 2015-03-27, 2015-02-17, 2015-01-29, 2015-01-20

> 3) Please give a detailed, precise description of what you think is going
> wrong.  No movies, no screenshots -- just a decent description.

I don't know the causality, but it seems like only part of the horizontal swipe gesture on the trackpad is being registered and then it just stops (in most cases).

I just realized this only happens when e10s is enabled. If I open the URL in a non-e10s window the swipe gesture is registered completely accurately. mconley: have you seen this before?

Comment 6

[Mike Conley (:mconley) (:⚙️)]

I suspect this is a dupe of bug 863514.

wlach - does the problem go away if you start scrolling downwards on the trackpad, and then attempt to pan without removing your fingers from the touchpad?

Comment 7

[William Lachance (:wlach)]

Yup, that's what happens. Resolving as a dupe.