1350829 - On Google Sheets, click-hold on the scrollbar track sometimes scrolls past the expected destination

Status: NEW

(Core :: Panning and Zooming, defect, P3)

Description

[ovidiu boca[:Ovidiu]]

Attachment: Recording #24.mp4

Tested on Mac OS X 10.10, MacBook Pro 10.12, Windows 10x64 using Nightly 55.0a1(2017-03-26).

STR: 

1. Open  https://docs.google.com/spreadsheets/d/1VCk6LAJ9g-El9e61cDzoysHahMU6wc3Qo2bPvau6frY/edit#gid=0
2. Click (press click continuously) in the middle of the scrollbar from the right side of the window.
3. Click (press click continuously) in the middle of the scrollbar from the bottom of the window.



Expected result: 

The scrolling is smooth, without any jerkiness or rendering issues
Scrollbar stops right where the mouse pointer is.

Actual result: 

In step 3 the scroll doesn't stop where the mouse pointer is.

Please see the attached video.

Comment 1

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

I can reproduce this in Release 52 as well, and on Nightly with apz.drag.enabled set to false. Doesn't seem to happen on Edge or Chrome.

Comment 2

[Botond Ballo [:botond]]

It happens with APZ disabled altogether, as well.

Google Sheets has JS-implemented scroll snapping that ensures that the top left corner of the spreadsheet's viewport correspond to the top left corner of a cell. The observed behaviour is likely an artifact of this feature.

The difference between Chrome and Firefox could still be a Firefox bug (though not an APZ bug, since the issue happens with APZ disabled). Realistically, that would require a minimal code example reduced from Sheets's scroll snapping implementation that exhibits different scrollbar behaviour in Chrome and Firefox, to diagnose.

I feel like the productive division of labour here would be, rather than us trawling through minified Google Sheets JS, the developers of Google Sheets preparing such a minimal example and providing it to us. I'm not sure whether we have a mechanism for coordinating such things - perhaps through Evangelism, or Platform Relations?

Comment 3

[ovidiu boca[:Ovidiu]]

Note: This doesn't happen on Ubuntu 14.04 x64 Nightly 55.0a1(2017-03-27), the same scenario from the description. I used a laptop with a trackpad.