1477995 - Surplus scrolling when stop autoscroll with mouse wheel over the autoscroll marker

Status: RESOLVED INACTIVE

(Core :: Graphics: WebRender, defect, P5)

Description

[Alice0775 White]

+++ This bug was initially created as a clone of Bug #1444845 +++

The problem is only happens with WebRender enabled.


Reproduce: always

Steps To Reproduce:
0. Enable WebRender
1. Open any long page such as http://archive.mozilla.org/pub/firefox/nightly/2017/12/
2. Middle click on empty area so that perform autoscroll (do not move mouse pointer)
3. Turn mouse wheel over the autoscroll marker

Actual Results:
Surplus scrolling occurs. And then the autoscroll marker disappears


Expected Results:
No such surplus scrolling. Just the autoscroll marker disappears

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I can reproduce on Windows. Given that the non-WR version of this was fixed by bug 1467867, this is likely a failure to propagate hit-test information from the UI process into the content process.

Comment 2

[Maire Reavy [:mreavy]]

Kats - How bad is this?  (I assume this is still reproducible.)  How likely is it that an nvidia chip user will hit this?

Comment 3

[Kartikaya Gupta (email:[e-mail])]

(In reply to Maire Reavy [:mreavy] Plz needinfo from comment #2)
> Kats - How bad is this?

Pretty minor interaction difference in the grand scheme of things. Doing the wheel scroll does also exit autoscroll, it just does a scroll *in addition* to that. Which is probably not a big deal; most people don't even use autoscroll and those that do likely use the middle-click to exit it. We can drop this from the MVP.

> (I assume this is still reproducible.)

Yes

> How likely
> is it that an nvidia chip user will hit this?

The codepath is hardware-independent, so it should affect all users.

Comment 4

[Kartikaya Gupta (email:[e-mail])]

If we fix bug 1536520 this bug will become a no-op, since mousewheel won't interrupt autoscrolling anymore.