1654509 - Address bar is slightly resized on the right side when opened

Status: NEW

(Firefox :: Address Bar, defect, P3)

Description

[Alexandru Trif, Desktop QA [:atrif]]

Attachment: adressbar_resize.gif

Affected versions

• 80.0a1 (20200721215127)
• 79.0 (20200720193547)
• 78.0.2 (20200708170202)

Affected platforms

• Windows 10x64

Steps to reproduce

1. Open Firefox and focus the address bar.
2. Observe the right blue side of the focus line.

Expected result

• Address bar opens as expected.

Actual result

• Right side focus line is slightly resized.

Regression range

• Last good revision: 94c8f28a15e8a051aeaad4722deb3fcc8125dab2
• First bad revision: bc2743384f7b58b56b00c9dbd33342c008a4b57b
• Pushlog:
  https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=94c8f28a15e8a051aeaad4722deb3fcc8125dab2&tochange=bc2743384f7b58b56b00c9dbd33342c008a4b57b

Notes

• Attached a screen recording.
• I cannot reproduce the issue in fullscreen mode or maximize.
• I cannot reproduce the issue on macOS 10.12 or Ubuntu 18.04.

Severity S3

Comment 1

[:Gijs (he/him)]

Wow, this is hard to see in that gif... So the problem is that the blue/black right-hand edge of the address bar changes when you click inside the address bar to bring focus to it - it first appears at some X coordinate, and then shifts slightly left a fraction of a second later.

I'm not sure why the min-width on the flexible spacers would cause layout confusion here (ie the contents of https://hg.mozilla.org/mozilla-central/rev/bc2743384f7b ), because I'm not familiar with the address bar side of things. Dão, maybe you know?

Comment 2

[Dão Gottwald [:dao]]

Maybe there's a rounding issue here:
https://searchfox.org/mozilla-central/rev/dcd9c2d2bc19d96d487825eb70c2333a4d60994e/browser/themes/shared/urlbar-searchbar.inc.css#201-202,216

But it's weird that the border shifts to the left with a delay... This doesn't seem to make sense.

There's also an animation involved here:
https://searchfox.org/mozilla-central/rev/dcd9c2d2bc19d96d487825eb70c2333a4d60994e/browser/themes/shared/urlbar-searchbar.inc.css#224,241

But that uses transform and therefore shouldn't affect the spacer.