1309375 - blue underlines appearing under the device dropdown list while scrolling

Status: RESOLVED FIXED

(DevTools :: Responsive Design Mode, defect, P1)

Description

[Kamil Jozwiak [:kjozwiak]]

When you scroll through the device dropdown list under the responsive design mode, you'll notice blue underlines appearing in the list. When you scroll upwards using the mouse, the underlines will appear. When you scroll downwards, the underlines will disappear once you go over them with the mouse.

I've added a quick video to illustrate the issue:
* https://youtu.be/FPrLMYZqxxg

STR:

* launch the latest version of m-c
* load mozilla.org
* get into responsive design mode via Hamburger Menu -> Developer Tools -> Responsive Design Mode
* click on the device list
* scroll up and down through the list using the mouse, you'll notice the blue underlines appearing in the list

Comment 1

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

I tried my best to reproduce this, but I can't seem to trigger it.  I am using a 2016-10-17 build on macOS 10.11.6.  I tried my existing profile as well as a clean profile.  I checked on a 1x and 2x monitor.

:kjozwiak, do you see this with a new profile as well?

Comment 2

[Kamil Jozwiak [:kjozwiak]]

I couldn't reproduce this with the latest version of m-c so I went through mozregression several times to see which bug(s) have fixed this problem. Each run pointed at bug#1283453. I also went through several builds manually and the timeframes appear to match up with the results from the mozregression results.

:jryans, it looks like the UI changes in bug#1283453 have also fixed this bug. If this lines up, we can probably close this bug.

mozregression results:
======================

Using:
* mozregression --find-fix --repo=mozilla-central --good=2016-10-18 --bad=2016-10-11

84:13.00 INFO: First good revision: 56b16d2eaa77c4639f624f1b8eb01da70b5f0227
84:13.00 INFO: Last bad revision: 44726da7a2869614b04e2193f17f6060bdbf4ceb
84:13.00 INFO: Pushlog:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=44726da7a2869614b04e2193f17f6060bdbf4ceb&tochange=56b16d2eaa77c4639f624f1b8eb01da70b5f0227

84:13.78 INFO: Looks like the following bug has the changes which introduced the fix:
https://bugzilla.mozilla.org/show_bug.cgi?id=1283453

manual results:
===============

* /nightly/2016/10/2016-10-12-14-39-19-mozilla-central/ - failed (reproduced)
* /nightly/2016/10/2016-10-13-03-02-04-mozilla-central/ - failed (reproduced)
* /nightly/2016/10/2016-10-14-06-03-24-mozilla-central/ - passed (couldn't reproduce)
* /nightly/2016/10/2016-10-15-03-02-03-mozilla-central/ - passed (couldn't reproduce)
* /nightly/2016/10/2016-10-16-03-02-05-mozilla-central/ - passed (couldn't reproduce)
* /nightly/2016/10/2016-10-17-03-02-09-mozilla-central/ - passed (couldn't reproduce)
* /nightly/2016/10/2016-10-18-03-02-11-mozilla-central/ - passed (couldn't reproduce)

Comment 3

[J. Ryan Stinnett [:jryans] (Use needinfo, replies may be slow)]

Aha, great!  I don't recall seeing this issue prior to landing bug 1283453, but it does alter the CSS for the drop down in question, so it seems like a reasonable explanation for why it's now fixed.

Thanks for the in depth analysis!