1292818 - Janky scrolling with scroll buttons only, everything else ok

Status: NEW

(Core :: Layout, defect, P3)

Description

[Keatah]

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:49.0) Gecko/20100101 Firefox/49.0
Build ID: 20160802125918

Steps to reproduce:

No special action. Simply go to a page, text or graphics, and try using the scroll buttons (up/down) onscreen arrows.

Version 39 for windows desktop was ok. The problem began with version 40 and persists through 49 (and probably higher)


Actual results:

Using onscreen scroll buttons (up/down arrows) results in in a rather jerky motion. All other methods of scrolling are butter smooth - wheel, mouse, keyboard, touchpad, all ok.

It like a continual starting and stopping action. Start. Stop. Start. Stop. When the content is actually moving it's smooth for a half a second. Then it stops for a quarter second (more or less). And then starts again.

It's the continual interruption of the smooth scrolling that's terribly annoying.



Expected results:

Expecting smooth continuous scrolling regardless which

Comment 1

[Emil Pasca [:emilpasca]]

User Agent: Mozilla/5.0 (Windows NT 5.1; rv:49.0) Gecko/20100101 Firefox/49.0

I have tested this issue on Windows XP x32 with the latest Firefox release (48.0), the latest Nightly (51.0a1-20160810030202), beta (49.0b2-20160808002253), Developer edition(50.0a2-20160810004000) and also with Firefox(39.0) and manage to reproduce it.
Using the latest versions of Firefox I have observed that when using the onscreen scroll buttons (up/down arrows) there is a slightly interruption of the smooth scrolling. This can be observed on various websites (e.g. 9gag.com, facebook.com and other pages).