1578715 - urlbarView is shown below the DevTools's border (splitter) when DevTools are docked to the side

Status: VERIFIED FIXED

(Firefox :: Address Bar, defect, P1)

Description

[Florens Verschelde :fvsch]

When DevTools are shown and docked to the side (~15% of DevTools sessions), the urlbarView shows below the DevTools's splitter border.

Firefox 70.0b3 and Nightly are affected.

It looks like both elements belong to the same stacking context and are both z-index: 1;.

/* browser/themes/shared/urlbar-autocomplete.inc.css */
.urlbarView:not(.megabar) {
  position: fixed;
  z-index: 1;
  …
}

/* devtools/client/themes/splitters.css */
splitter.devtools-horizontal-splitter,
.devtools-side-splitter {
  …
  position: relative;
  /* Positive z-index positions the splitter on top of its siblings and makes
     it clickable on both sides. */
  z-index: 1;
}

Setting the z-index for urlbarView to any value above 1 seems to fix it.

Comment 1

[Florens Verschelde :fvsch]

Attachment: urlbar-devtools-splitter.png

Comment 2

[Dão Gottwald [:dao]]

Attachment: Bug 1578715 - Increase urlbarView's z-index. r=mak

This is the same value we now use for the megabar: https://searchfox.org/mozilla-central/rev/878bbf3cb8897a208454df27535f3522ab482cf2/browser/themes/shared/urlbar-searchbar.inc.css#118

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a67d0c7d97aa
Increase urlbarView's z-index. r=adw

Comment 4

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/a67d0c7d97aa

Comment 5

[Dão Gottwald [:dao]]

Comment on attachment 9092619 [details]
Bug 1578715 - Increase urlbarView's z-index. r=mak

Beta/Release Uplift Approval Request

• User impact if declined: see comment 1
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: dock devtools to the side and type in the address bar
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): trivial fix
• String changes made/needed:

Comment 6

[Liz Henry (:lizzard) (relman/hg->git project)]

Comment on attachment 9092619 [details]
Bug 1578715 - Increase urlbarView's z-index. r=mak

Fix for regression in 70, fine for uplift for beta 7.

Comment 7

[Andrei Ciure[:aciure]]

https://hg.mozilla.org/releases/mozilla-beta/rev/259a6f1dfb07

Comment 8

[Timea Zsoldos [:zstimi/tzsoldos], Desktop QA]

I have reproduced this issue using Firefox 71.0a1 (2019.09.04) on Win 10 x64.
I can confirm this issue is fixed, I verified using Firefox 71.0a1 latest nightly and 70.0b7 build from Treeherder, on Win 10 x64, Ubuntu 18.04 x64 and macOS 10.14.