1328071 - [e10s] list of options in <select> doesn't scroll smoothly when I click on scrollbar

Status: NEW

(Core :: Layout: Form Controls, defect, P3)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
STR_1:
1. Open attachment 8557479 [details]
2. Click on <select> to open list of options
3. Hover mouse over the vertical scrollbar, but not on the scrollbar thumb
4. Click

AR:  List of options teleports to new position
ER:  List of options should smoothly scroll to new position. References of that behavior:
  1) non-e10s
  2) both e10s and non-e10s if in Step 4 I rotate mouse wheel (My mouse wheel is configured
     to "scroll by 1 screen", so I expect the same action for (2) and Step 4).
  3) both e10s and non-e10s if in Step 4 I double-click or triple-click instead of just clicking
  4) both e10s and non-e10s if in Step 4 I hold left mouse button and list scrolls automatically

You should check regression range.

This is regression from bug 1235478. Regression range:
> https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=978349072992b565123bcd97e0778abaa7a67256&tochange=66252157547f3f4e0b9ad9fb3b0b96d6df5938fe@ Hiroyuki Ikezoe (:hiro):
It seems that this is a regresion caused by your change. Please have a look.

Comment 1

[Hiroyuki Ikezoe (:hiro)]

Is the regression range correct?  I can see the same behavior between today's nightly and 2016-01-01 nightly.

Comment 2

[Timothy Nikkel (:tnikkel)]

Regression range seems a bit fishy to me too. I would double check it before investigating further.

Comment 3

[Ryan VanderMeulen [:RyanVM]]

I tried re-bisecting this and was definitely able to reproduce the jankiness reported in this bug, but I've still had a difficult time bisecting it down to a culprit commit. I can also reproduce the janky scrolling prior to bug 1235478 landing.