1416797 - Middle Click sometimes doesn't toggle scroll mode

Status: NEW

(Core :: DOM: UI Events & Focus Handling, defect, P2)

Description

[FO-nTTaX]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171103003834

Steps to reproduce:

I middle click repeatedly and the indicator of scrolling being enabled doesn't toggle reliably.


Actual results:

So this is similar to https://bugzilla.mozilla.org/show_bug.cgi?id=1099491, but still happens to me in the current developer edition (fully updated as of 2017-11-13). I made a video here: https://www.youtube.com/watch?v=DL47OT2QOb8

Sometimes it just doesn't do anything, at like 10 seconds into the video it starts flickering.


Expected results:

The scroll indicator/scrolling should toggle reliably.

Comment 1

[Andrew Overholt [:overholt]]

I don't know how we trigger that functionality. Jim, do you?

Comment 2

[Jim Mathies [:jimm]]

I can reproduce this. You trigger it with middle click, on my mouse there's a button integrated into the wheel you press for this.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

Is this related to bug 1390247?

Comment 4

[Andrew Overholt [:overholt]]

(In reply to Jim Mathies [:jimm] from comment #2)
> I can reproduce this. You trigger it with middle click, on my mouse there's
> a button integrated into the wheel you press for this.

Sorry, I should have clarified: I know how to trigger it but are we somehow not sending the middle-click event to Windows to enable this mode?

Comment 5

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

We handle it internally, not via Windows. The code starts around https://searchfox.org/mozilla-central/rev/550148ab69b2879bfb82ffa698720ede1fa626f2/toolkit/content/browser-content.js#279-285

Comment 6

[Botond Ballo [:botond]]

I'm not able to reproduce this. Scrolling the mouse wheel between clicking and releasing it does make the autoscroll indicator go away, but that was the case before the APZ autoscrolling changes, too.